That sounds like some seriously weird co-workers. I don't deal with any cocaine users in any of my past work history, just occasionally meeting people from work to smoke marijuana with and even that was bad for me. I just dealt with an addiction problem that my roommate had. I had to kick him out of the house because it got so bad that he had lost his mind. When you have something good going for you, like a family or just your sense of self-esteem you can't let others walk over you and damage the wholeness of your being. If you give in easily than stay away from that behavior for I believe it to not be beneficial at all.

I have a personal care assistant because of my disability that I live with now, and she said at a past job, she was tired and a group of men told her she looked tired and that she should try smoking something that she thinks was meth, she wasn't sure, or crack. Anyways she spent the next 48 hours cleaning the walls of her apartment because she was convinced they were dirty. Her kids came over and saw what madness the drug had caused in her and she started to cry and said she didn't know why she did it. Thus to say, she quit that job and became a personal care assistant to help the disabled, and she feels much better about herself now though she can barely pay all the bills for her health care as she is 65 years old, doing my dishes and cleaning my floors.

Sometimes if people are a bad influence on you, either you take a stand against them and if that means they will fire you or bad mouth you, than it is time to find people or a job where there are healthy people to be around.