Hello again.
May I ask what type of relationship you have with your daughter? I sense an apprehension on your part to have a heart to heart. She is likely the only one that will be able to enlighten you. This will ultimately cast aside the assumptions, and bring you some real answers. You do deserve these answers. You are clearly very hurt. You are absolutely allowed to hurt. I wasn't the greatest communicator in my teen years...not much better now. Please, approach her and ask her how she feels and why she feels the way she does. Maybe the answers will be unpleasant, or maybe they won't. Teen years are rough. Being a teenage girl is extremely difficult. Ask her how she feels...