First I don't think you are insane.

Can you talk to your counselor at school?

Your parents have to know there is some issue with you losing weight, I would suggest a full physical by your family doctor, then a referral to a psychiatrist and to start seeing a therapist.

You are going through a very tough age, I know this will sound like I'm trivializing your situation and that is that last thing I want to do, but things do get better