Salvation is dependent upon what Christ did on the cross, not on what you did, do, or will do (or won't do):
Ephesians 2:8 For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: 9 Not of works, lest any man should boast. 10 For we are his workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them.
The only proviso / qualification on your part is belief:
John 3:16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. 17 For God sent not his Son into the world to condemn the world; but that the world through him might be saved. 18 He that believeth on him is not condemned: but he that believeth not is condemned already, because he hath not believed in the name of the only begotten Son of God.
1 John 2:19 assures that the believer will not depart the faith, that if they do depart they never believed to begin with.
1 John 2:19 They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us.
But the good news is, even if you never believed in the first place and you are still alive enough post here, you can believe now and be saved.
As far as falling away for a time, it can and has been done by believers. Part of that blessed assurance of salvation is that if we as believers walk away and are too stupid to give up our worldly ways... God will take our lives in this world before we can lose our soul.
1 Corinthians 5:5 To deliver such an one unto Satan for the destruction of the flesh, that the spirit may be saved in the day of the Lord Jesus.
searching4something said:
From your post and that which you are unwilling to post (because it's nobody's business anyway) you have good reason to feel bad spiritually. We believers have the HOLY Spirit living inside us. That's not just a superfluous name, it describes him as well. He is HOLY. And our unholiness grieves him. And his grief has to manifest itself in our hearts if he is truly resident there.
Oh sure, caving into temptations and what appear to be short cuts or fixes somehow are all too easy a trap to fall into. And sometimes we sin delivberately knowing full well its sin. But we are God's property. And more importantly, God loves us. And he's not going to let us just sin sin sin with impunity. He's active in our lives and takes us to the woodshed for a whipping when we need it. It may be a feeling of loss, it may be a lost job or home, it may be a million different things. God knows what is effective and what is not. But he is never going to withdraw his love or his salvation from his people.
Why, repent of course.
1 John 1:9 If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.
This does not mean confess to a priest or pastor. In the original Greek it means "If we agree with him our sins (are sins) he is faithful and just to be / being forgiving our sins cleansing us from ALL unrighteousness.
It simply means as believers God's forgiveness is ongoing and ALL unrighteousness means ALL unrighteousness (including whatever you think you did beyond what God could ever forgive). And the confession is really coming to terms with God that you know what you did is wrong. He's not fooled.
I was a Christian. Gosh I remember my baptism like it just happened five minutes ago.
Once again, you cannot lose or give away your salvation.
I have fallen away....well don't know if it is fallen away, as much as never gave up all the sins.
As others have posted here, you won't have given up all sins until you are dead.
Romans 6:7 because anyone who has died has been freed from sin.
This verse doesn't mean the dead are saved by dying it means we are no longer under the temptation of the body.
Paul the Apostle had his moments feeling the way you do but with full assurance of his salvation:
Romans 7:1 Do you not know, brothersfor I am speaking to men who know the lawthat the law has authority over a man only as long as he lives? 2 For example, by law a married woman is bound to her husband as long as he is alive, but if her husband dies, she is released from the law of marriage. 3 So then, if she marries another man while her husband is still alive, she is called an adulteress. But if her husband dies, she is released from that law and is not an adulteress, even though she marries another man. 4 So, my brothers, you also died to the law through the body of Christ, that you might belong to another, to him who was raised from the dead, in order that we might bear fruit to God. 5 For when we were controlled by the sinful nature, the sinful passions aroused by the law were at work in our bodies, so that we bore fruit for death. 6 But now, by dying to what once bound us, we have been released from the law so that we serve in the new way of the Spirit, and not in the old way of the written code. 7 What shall we say, then? Is the law sin? Certainly not! Indeed I would not have known what sin was except through the law. For I would not have known what coveting really was if the law had not said, Do not covet. 8 But sin, seizing the opportunity afforded by the commandment, produced in me every kind of covetous desire. For apart from law, sin is dead. 9 Once I was alive apart from law; but when the commandment came, sin sprang to life and I died. 10 I found that the very commandment that was intended to bring life actually brought death. 11 For sin, seizing the opportunity afforded by the commandment, deceived me, and through the commandment put me to death. 12 So then, the law is holy, and the commandment is holy, righteous and good. 13 Did that which is good, then, become death to me? By no means! But in order that sin might be recognized as sin, it produced death in me through what was good, so that through the commandment sin might become utterly sinful. 14 We know that the law is spiritual; but I am unspiritual, sold as a slave to sin. 15 I do not understand what I do. For what I want to do I do not do, but what I hate I do. 16 And if I do what I do not want to do, I agree that the law is good. 17 As it is, it is no longer I myself who do it, but it is sin living in me.
18 I know that nothing good lives in me, that is, in my sinful nature. For I have the desire to do what is good, but I cannot carry it out. 19 For what I do is not the good I want to do; no, the evil I do not want to dothis I keep on doing. 20 Now if I do what I do not want to do, it is no longer I who do it, but it is sin living in me that does it. 21 So I find this law at work: When I want to do good, evil is right there with me. 22 For in my inner being I delight in Gods law; 23 but I see another law at work in the members of my body, waging war against the law of my mind and making me a prisoner of the law of sin at work within my members. 24 What a wretched man I am! Who will rescue me from this body of death? 25 Thanks be to Godthrough Jesus Christ our Lord! So then, I myself in my mind am a slave to Gods law, but in the sinful nature a slave to the law of sin.
I feel like I am not worth of God's love.
None of us are! Remember the Apostle Peter in the face of the righteousness of Jesus, "Depart from me, Lord, I am a sinful man!" (Luke 5:8). And Isaiah when he saw the righteousness in the Glory of God he said "Woe to me, I am a man of unclean lips..." (Isaiah 6:5), then let's not forget King David comitted adultery, Moses murdered an Egyptian, and so on (if you get the impression that Peter and Isaiah were pious men).
How could he love me, or want me to be in his flock...
That's the question of the ages. For we can all wonder this and fill in the blank with our sins (where I deleted your particular list of sins). There are many theological speculations and even denominations (the election versus free will argument) which I will not get into here. It's enough to say he does love you and everyone of us to have sent his Son to die for our sins that we would have the opportunity to be saved. That's a greater love than we can truly imagine in this life, but suffice it to say it is love nevertheless.
I can't control due to mental illness.
Believe it or not diagnosing mental illness is a slam dunk (if you actually had it diagnosed) because I believe we all suffer from some form of it due to our fallen sin nature. I mean, look at our track record. God said "universe, exist," and it lept into existence. God says to us "Go..." and we say "No. I don't want to." That HAS to involve a certain amount of insanity because God has control over our next [inhale] breath [exhale].
I am not compassionate, but can't control it.
Honk at the rude driver that cut you off on the way to the store did you? Oh you flicked him off?

Let me let you in on a little secret. I don't have Jesus stickers and bumper stickers and fish symbols on my car because I occasionally loose my cool at stupid drivers on the road. And I don't want that to be a reflection on God at all. Perhaps the only time it's ok to be a secret agent Christian. L

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I don't feel I can walk back into the church I was going to.
Go to another then. As a Christian you are a member of every Church that is truly Christian. For we believers are the Church:
1 Corinthians 3:16 Dont you know that you yourselves are Gods temple and that Gods Spirit lives in you?
I can't bring myself to pray or worship.
Just do it. Break out the book of Psalms in your Bible and start reading aloud and conclude in Jesus' name. And voila! You've prayed, and probably learned something too. Psalm 51 is a good one if you are contrite (remembering that on this side of the cross God will not ever take his Holy Spirit from us [verse 11 seasoned with Hebrews 13:5b])
Satan has such a hold of me.
No, he just has you thinking he does. It's an old fallen angel trick. Believe God and his Word for they are true (John 3:33 and John 17:17) and Satan is the father of lies (John 8:44).
This is actually a good thing, because it is strong evidence that the Holy Spirit is living in you. If you really belonged to the devil (which is the only other option) then you would not be concerned or even aware there was a problem.
Find assurance and comfort in these facts.
God bless.