What Am I Supposed to Do After My Life Inside a Drug Rehab?

I just got out of a drug rehab. I feel good and I think I made the right choice. What am I supposed to do now? I’m 21 years old and I know that I have a good life ahead of me but I just can’t seem to figure out where to start. I can’t even go back to my old friends. They’re still holding pot sessions. I don’t want to risk my recent recovery. Any suggestions on what I can do to continue a healthy life?