I've lost friends due to my manic behavior, and found it's hard to impossible to reclaim them. I know you feel awful. I felt shame and anger for a long time afterward, but I fianlly put it behind me and moved on. We can't dwell on what we can't change.

Sounds like you are doing what you can by stopping the drug use. Maybe your friends will see your change and give you a second chance. I hope so.