@woohoo I do not have any familiarity with fas, nor have I been around people who suffer with this. But I am familiar with depression. Fifteen is an awkward age without any issues, add in these factors, and it becomes a challenge for everyone. If this is her first year at a new high school, students can be such bullies. Perhaps there was an incident that has turned her away from that location? The person who told you about her anger and sadness being connected may really be on to something. Expressing love and support from you and your husband, letting her know she has a safe place with you, and you will do anything to help, will go a long way, I believe.
Ginger