Should I be concerned about my daughter?

When life throws a curve ball, such as your daughter's friends suddenly turning on her and treating her bad, it can skew up your whole life plans. It seems to me that she is just having difficulty deciding which direction to go. Be patient and supportive. Don't give her any ultimatums, that will only make her resentful of you and push you further out of her life. She just needs some time to figure things out.