What's the worst friendship fallout you experienced?

My “best” friend asked me to go to a Con with her in DC for a few days. A couple weeks before I had to go to the hospital for over a week and was put on anxiety medication and a mood stabilizer. She started taking some of my pills, but I didn’t feel bothered I knew she had a thing for Xanax here and there and my medicine was much weaker. Anyway, we get there and she takes a Xan. Still no biggie. I told her I’d buy her a drink since she payed the hotel (I paid plane tickets). She proceeds to order to margaritas and she’s not even a drinker to add to the Xanax. I had my normal one anxiety pill and a drink, but I’m still pretty spaced out and tired from the hospital stay. She wants to go to the rave and we had so much fun at the one 9 months before for my birthday so I agreed. We get there and I suddenly feel uneasy and exhausted. I told her to enjoy and I’d sit there and watch her. She got absolutely pissed that I would ruin her trip that way the same way her husband did at the lost con she went to (I had no idea). She proceeded to say I was hooked on my pills. Then when we got back to the room she started packing and was yelling. I told her I didn’t feel comfortable with how she was acting. She said if she was really violent she could hurt me if you wanted to and held a fist a few inches from my face. At that point I feel unsafe so I called my bf in SC (who was working a shift of 6-2am) and asked him to come get me. She got pissed I left her in DC alone, but that’s not what I needed after the hospital stay. I’m so grateful my bf came and got me because it was awful. Turns out her husband message me she is taking Xanax regularly now. He’s upset because he’s a recovered heroin addict, and doesn’t like that she doesn’t respect how upset it makes him. He won’t bring it up to her any more though.