Some of your examples are making me think BPD - but of course she's not technically an adult yet so even if a personality disorder was the case they wouldn't diagnose her at the moment. However, some of the treatment options for that disorder or others might still be available to her and i think taking her to a professional is a sound idea - if anything they'll have advice on what to do if they don't think there's anything wrong specifically. In either case, maybe family therapy would also be a good idea? It would help all of you deal with this situation in a more productive, monitored way. I hope you find some peace with this situation soon. Keep posting, we're here to help