Feeling unworthy

I have very few friends. Actually 3. Two of which smoke weed. I on the other hand do not smoke weed because I've had a bad history with it and it leading to my involvement in pills. My one close friend is always hanging out with the other and they're smoking weed and having 'dankening' parties (smoking weed and eating chips and dip etc.). My only other friend who doesn't smoke has issues with my fiance, they're constantly at each other's throat because he has a " mean sense of humor" and he thinks she's immature. My closer friend has now blown me off twice recently, last week she said she had to work and I found out she was with the other friend smoking, and this weekend she was supposed to sleep over but instead passed out at the others house. It makes me feel unworthy and that I would have to smoke weed to even be fun to hang out with anymore. Of course that's not what I'm going to do but I don't really know what to do. Should I confront her and tell her that's how I feel or just let it go?