Those are phrases that many ppl fall back on when they don't understand, or are unable to address problems, imo. "making it all up" or "it's all in your head" are common dustoffs

I have an attorney who still doesn't understand that my problems are not all in my head...and she's a professional adult paid to represent me. It doesn't mean she's correct.
I would hope you would continue to pursue getting yourself help. Perhaps through your school. If that's too far away in time, then call one of the teen hotlines (800#) and chat with someone there who is very familiar with the ppl who are in your area to help you.
Parents just don't understand sometimes. I'm sorry. But while you must respect her, you can continue to seek real help. Do you see the family MD each year before school? Then surely you can ask her/him for help! That's what they want to do. If you can't get your mom out of the room, then forge ahead and ask for help anyway! Sometimes taking care of ourselves is tough, but it's always worth it!
TC!