You should not defile your body with substances as it does not belong to you, it belongs to God, for Jesus died and bought you. Also, it should be kept as undefiled as possible as the Holy Spirit abides there.
1 Corinthians 6
19 Or do you not know that your body is a temple of the Holy Spirit who is in you, whom you have from God, and that you are not your own? 20 For you have been bought with a price: therefore glorify God in your body.
You have told us that you dont know Gods will. Gods will is basically what he would have you do, e.g. help others, abstain from sinful actions etc. Do what is Godly and not what is evil or disobedient to him. Dont do anything that you know is wrong.
When people say, go to God they mean pray to him and ask him for help. God does not stay in heaven and never comes out, God is everywhere and he knows more about us than even what we know about ourselves. God can be spoken to at anytime. You dont even have to literally speak the words; you can just pray to him in your head.
Pray to the Holy Spirit. Perhaps you have done a lot of wrong, or have done something to grieve the Holy Spirit.
Ephesians 4:30
Do not grieve the Holy Spirit, by whom you were marked with a seal for the day of redemption
You say you have never felt him (God). But you seam certain your going to heaven. Are you sure youre truly saved as someone who is saved normally has felt God.
You should not carry on sinning i.e. substance abuse. We will all continue committing sins now and again as we are weak and the devil can deceive you when you have lost your peace.
Luke 4:30
35 Be dressed in readiness, and keep your lamps lit. 36 Be like men who are waiting for their master when he returns from the wedding feast, so that they may immediately open the door to him when he comes and knocks. 37 Blessed are those slaves whom the master will find on the alert when he comes; truly I say to you, that he will gird himself to serve, and have them recline at the table, and will come up and wait on them. 38 Whether he comes in the second watch, or even in the third, and finds them so, blessed are those slaves.
39 But be sure of this, that if the head of the house had known at what hour the thief was coming, he would not have allowed his house to be broken into. 40 You too, be ready; for the Son of Man is coming at an hour that you do not expect.
41 Peter said, Lord, are You addressing this parable to us, or to everyone else as well? 42 And the Lord said, Who then is the faithful and sensible steward, whom his master will put in charge of his servants, to give them their rations at the proper time? 43 Blessed is that slave whom his master finds so doing when he comes. 44 Truly I say to you that he will put him in charge of all his possessions. 45 But if that slave says in his heart, My master will be a long time in coming, and begins to beat the slaves, both men and women, and to eat and drink and get drunk; 46 the master of that slave will come on a day when he does not expect him and at an hour he does not know, and will cut him in pieces, and assign him a place with the unbelievers. 47 And that slave who knew his masters will and did not get ready or act in accord with his will, will receive many lashes, 48 but the one who did not know it, and committed deeds worthy of a flogging, will receive but few. From everyone who has been given much, much will be required; and to whom they entrusted much, of him they will ask all the more.