My daughter is 15 so about your age & has recently had the medical year from hell with a misdiagnosis of anorexia nervosa (teenage girl eating issue &/or weight loss = anorexia nervosa/bulimia) whereas in fact when we found a dr/psychiatrist who considers family medical history her beliefs, behaviours & does blood tests, eeg & so on & we find that she's always felt that she had to please everyone & always felt guilty for everything (even if it had nothing to do with her). 6 weeks ago she was on the verge of a breakdown & maybe suicide/homicide of a dr or nurse & weighed 34kgs (about 70lbs) now she's 38kgs, out of hospital & starting to be a better healthier (mentally) version of her old self.
What changed (well despite the attack i'll probably get from another user) this dr put her on 50mgs at night of 5htp (a supplement of tryptophan which works to balance the serotonin levels in the brain & so reduce stress) & she has to take a 30 minute walk between 6 & 7 am because at that time there's siomething in the suns rays (even if overcast) that helps reduce stress. She doesn't have to see this dr again till april.
See if you can get blood & urine tests done (liver & kidney function tests plus sugar & cholesterol levels) also an eeg & brain scan(which if you're stressed is likely to show the right side of your brain as red & the left as white which is what my daughter's showed. As to the rest of her false beliefs (guilt etc) once she started to get better she with some counselling & group therapy began to recognize her problems & then was able to learn how to start to deal with them.
If you have a panic attack, first if driving stop, park wait it out!! Second if not driving find somewhere to sit & take some deep breathes & have a cool (this is what is usually needed but hot might work for you, we're all different) drink, then continue on your way when when you feel better.
Obviously you love your mum & i'm sure she loves you & she will be aware that you're not well but are you really communicating with her, she can help you & give you support. Sure she'll be upset & all that but as a mother I can assure you that you feel alot less upset & worried if your child is really talking to you & letting you help - she may have some insights that will help but you need to talk to her.
Take care christy & email if you need to talk out of forum.