Not the same thing then. If you did not verbally deny Jesus as your Savior, and you do not speak bad words against the Holy Ghost, you can be forgiven.
For if we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness (1 John 1:9). Jesus says we are to forgive a person 70 x 7. This means God can forgive us like that, too (And more). God is not willing that any should perish, but that all should come to repentance.
1 John 1:9 is a promise you can bank on. If you believe by faith that verse, then you are forgiven according to that verse. The feeling of God's Spirit in your life will come in time. The healing will come in time. But you must believe 1 John 1:9. It is 100% true. In fact, go to 1 John 1:9 right now and tell the Lord again how you are sorry. Tell the Lord that you believe His promise in 1 John 1:9 and that you will now live your life for Him. Don't wait for a feeling. Just believe 1 John 1:9. You have to believe it.
Solomon sinned a lot more than you and he was forgiven by God in the end. In fact, he wrote actual books in the Bible. Do you think God would let an apostate to write books in the Bible? The words of Scripture came about by the working of the Holy Spirit through men of God and not by apostates.
Anyways, Solomon went after other gods and had many wives and concubines. Yet, he concluded in Ecclesiastes that these things did not satisfy him. He concluded that we are to fear God and keep His commandments.
If you are interested, you can check out my thread on how I believe Solomon was saved in the end (According to Scripture):
https://www.christianforums.com/threads/was-solomon-saved.8055573/
Grievous sin does separate us from God, and it's wake might make us feel distant to God, but we have to walk by faith first. Walking by faith will in time give you the joyful presence of the Lord in time. But it starts with 1 John 1:9 (i.e. Repentance). But we do not believe just by having a feeling. The joy of the Lord will come in time. For David cried to the Lord to return to him the joy of his salvation back. He also felt as you did in Psalms 51. David committed adultery and murder. He also had many wives and concubines. He also disobeyed God in regards to giving a census. Yet, he was forgiven in the end because he kept seeking after God. David was a man after God's own heart. They that wait upon the Lord will renew their strength. That's what you need to do. Wait upon the Lord until He renews your strength in Him. It's faith. Not a feeling. Feeling will come in time, but believe in God's Word by faith.
Side Note:
I know your contention may be Hebrews 3:13-14, Hebrews 6:4-6, Hebrews 10:26, and Hebrews 10:38-39.
But you have to realize that this is talking about denying Jesus as Lord. The author of Hebrews was telling certain Messianic Jews who wanted to avoid persecution for a while by going back to the Jewish religion for a while until the persecution passed. But the author of Hebrews appealed to them about how Jesus is the Heavenly High Priest of a better covenant. We can see this push that Jesus is our priest in Hebrews 4 through Hebrews 5, and Hebrews 7, Hebrews 8, Hebrews 9. They wanted to come back to Jesus intentionally later on in their life after having regressed back to Judaism. But the author of Hebrews is telling them that if they were to do that, they would crucify the Son of God to themselves afresh (or all over again), thereby putting Him to an open shame (And they could no longer repent of their sins if they did that). So basically, they were intentionally wanting to deny Jesus by becoming Jewish in order to avoid persecution. This is not the same as just falling into sin in general. James 5:19-20 and the Parable of the Prodigal Son both teach that a believer can come back to the faith to the saving of their soul from living a prodigal life or in backsliding into sin. As long as you did not intentionally set out to deny Jesus and you did not not verbally reject Jesus, you can be come back to the faith and have assurance of salvation (in time), once you allow the healing process to take hold on your life by God.