Just support her.  Meds at that age are questionable, even like Ambien.  I've had insomnia for as long as I can remember.  If she's in regular school, that makes it harder because she has to get up early.  I work nights, so that helps me.  I would stay off med's as long as possible, let her grow.  Unless she becomes suicidal, then all bets are off and its life-saving med time.  Is she still seeing a therapist?  She may need more therapy.  I had three full years, it helped me look at life in a different way.  Also take into consideration her life away from home- school, is she liked, bullied, popular, left out?  Anything can give a teen anxiety, they're not ready to deal with middle school, high school.  Just let her talk and you just listen, make that a habit.  Go from there.  I hope that helps,

Stephanie