I'm fairly young, but alot of what you are going through i can relate to. I went through a few rough months, of eph, pv, gabergic and kratom abuse. Then got my shit together over the summer, and it just happened again. Don't beat yourself up over it, most people can relate to problems with bad habits, and stagnation of life thats only result is ending up in a deep hole to climb out of, but i did it again.
What worked for me, was just saying i'm going to do everything i usually don't do because i want to get high, as soon as you get up in the morning. Find new intererests, find something that brings you peace and happiness. It might take a while, but you can force your mind to work how YOU want it to work. It just takes time and effort, and faith in yourself to do so.
Life is to exquisite and theres far to many possibillitys and expirences to enjoy, to fall into these patterns that destroy physical/mental health, and exasperate pre-existing conditions (for me it was depression/social anxiety) to the point it hurts so bad you want to find a way out.
Theres two options, the easy way, and the one that only dissalows any further opportunity of happiness and living healthy/loving others, yourself and the world, at the expense of a unknown possibility that killing yourself will take the pain away. Thats beyond the realm of deviation before doing so, and theres no going back.
The hard way, is to turn around and look at your shadow, look at yourself, make no illusions about who you are and why you are what you are. Then tell yourself you can change what you don't like, and fuck anything that gets in the way of that. Its possible, and theres a chance you might find resolution to some of that pain, and a better/happier existence than where you are now.
I know that probably all sounds cliched, and you've probably heard it before, or belive parts of it. I just hate to see BL'ers who are hurting continue to hurt themselves, when theres always another route to take. Know your not alone, and that drug counseling/external help can help, but the solution is within yourself. Its deep down, buried under all the shit, just itching to get out.
I hope you find yourself in a better place, and take care of yourself. Theres always a way to spend your life that makes you and others happy, which makes you happier and more content with life. Escape the patterns, take it slow, don't be quick to trade in for another bad habit.
I spent a summer taking psychadelics and eating healthy, working hard, and exercising hard after a winter of my discontent in drug abuse. It sucked at first, but given time i became happy and healthy again, and felt like i was living my life how i wanted to do so. That involved admitting and accepting my flaws, then doing something about it. To do otherwise would be insanity, or what i was trying to escape from.
I hope you have family or friends that you can talk with about this, people in general are wonderful and kind most of the time, and it helps to get your problems out there and a different perspective you can gain valuable perspective from.
IF nothing else, push on to resist what you abhor, and try your hardest to vanquish it. Drug abuse to deal with that pain, is kinda like killing yourself. Your odds are better if you choose to embrace life and change yourself.
I'm young and cocksure at giving advice about this stuff, this is just what worked for me. Know others have found solace using other methods. You never really know what offing yourself will accomplish, the only thing for sure is it will cause great pain and suffering upon others close to you, and to dole out what you are expirencing upon others to try and alleviate your pain, seems like a pretty shitty thing to do.
Reach out to others @ the dark side who can give more wise advice than i can, i just hope you can find a way to ease that pain, and not cause the same pain upon others, many can relate and love you for who you are and what you can be, no matter what you are now.
SRV - Life without you 
From 5:20 on is whats most important.
