So i get you in the sense that although i don't do art GCSE, My two best friends do and when ever they get out of art they feel drained as hell! Their art teacher said if you want to priortise your other subjects then be happy with a 5-6. I also want to get into medicine and I am not going to lie to you but they care about extra-curicular activities,etc. My Advice is do what make you happy cause in the end of the day it is you that is doing all the other subjects. and if youre not doing art in later in your life then why make it something that is a burden. Manage your time to ensure you are confident in your other sumbject, get the time with your family etc, then do art in your spare time. Sit your parents down and show them how much work you need to do for art and explain to them calmly your stress and issues. As for Dropping your subject, assuming you are in yr 11, in really depends on your school. I know people that got their parents to contact the school to tell them to drop a subject. So first truly explain to your parents what is wrong, acknowledge you naivity in yr9 where you thought art was easy and tell you parent what you said here. Don't bottle your stress. Hope this helps!