Don't listen to what your relatives are saying. They don't know, and they don't understand. You know how people are: They talk even if they don't know what they're talking about. So don't listen.
Being scared is normal, but the people in that room have the same problems, the same concerns, and they are also scared of being judged or not understood. And you can always turn around and run like hell!
However meetings are the best. You can relate with some people, you hear things that help you look at your problems in a different way, you realize you are not alone. Give it a try and let me know how it went.
Since you're officially out of drugs at home and since it's gonna suck big time, try a meeting, or two, or three. Serious. It's worth it.