I agree with Anniebrooke. Keep at it. I'm glad you see the pot smoking as the problem it is. and often we use drugs to cover our depression/anxiety. Drug abuse often goes hand in hand with this. I'm sorry you're suffering!
Do you do counseling? You don't mention this.
peace
Sweetheart, you're starting the way you should, in small steps, please give yourself credit and keep taking the small steps. You're using the drugs to block out having been through way too much, but the supposed "cure" is going to kill you, as you say. So the next small step is to find a counselor, and to begin working on the mental part of the tangle. Again, small steps. Your mind won't let you work on things that are too much to bear, it's like uncovering logs floating in a log pond, you take the first layer off and see what comes to the surface next. You can only work on what gives you the pain as you are ready to work on it, but frankly, it sounds like you are ready to work on some of it, or you would just be sitting around in a mj-fueled haze and saying you were OK.
See a good counselor, and just tell the broad story of what happened, and see what logs move. The more you unload mentally, the less you will need to do to get blotto physically.
Good luck, it sounds like you can do it.