Your daughter is showing signs of severe emotional disturbance that sound similar to Borderline Personality Disorder. She may have ADHD, but it is likely she has something else also. It is possible she has suffered serious trauma or abuse such as the bullying suggested above.

You should take this behavior VERY seriously. Your daughter needs extended and expert help, she is also going to need significant emotional support from everyone in her life.

I have seen kids like your daughter before (from your description anyway). You need to minimize ANY external pressures on your daughter and have her accessed by an expert. She sounds at high risk of putting herself in extreme danger. She is not coping psychologically.

(All this is just my personal opinion from my own experiences)