I am fairly certain I wouldn't be able to stay sober if I was constantly surrounded by drinking and drugging. I suppose I got lucky that I have a teetotaling Wife who has never touched a drop. I stopped hanging out with most of my drinking buddies years ago when I moved on my own for work.
The only safe way to truly try to get sobriety right for you is to not put yourself in harm's way. I know this has got to be a tough choice for you but I honestly can't say your chances of staying sober are very good if you stay in this toxic environment.
Sorry you are dealing with some tough temptation.