I'm getting really stressed but i dont think my parents understand?

this year has been the most stressful year. i'm a junior which i know is an important year and i already had 3 tests. i bombed one because the teachers an a$$ and gave 10 minutes to do the test! i couldnt answer two questions so i got a friggen 70! besides this i'm taking honors/college/reg. cles plus French 3. all my teachers except one are crazy. after school i have dance team mon,tues,weds,thurs for 2 hours after school. on mon,tues,weds i have reg dance a half hour away for 2 hours. on weds i have an sat cl for 3 hours which means as soon as i get home from dance team i have one hour to shower/eat/do homework before going to the cl. on fridays i have dance team practice whenever my coach feels like it! i'm also on homecoming/prom committee. i'm not allowed to quit anything but im getting super stressed to the point where i have cried almost every single night. whenever i attempt to vent to my parents they get annoyed to where my dad tells me to stop my complaining. the only free day i get is sunday since saturday i have comp. practice for dance smack in the middle of the day. also when i get home i have chores which take up a good half hour and i also get two hours of homework a night. now my mom is making me get a job if i even want to take my road test! i dont have time! who would hire me one day a week? the one day i have to just hang with friends i have to give up? it's so frustrating and all my teachers prob think i'm a big failure since i bombed that one test and only did okay on other quizzes. i know my parents are trying to understand but idt they really know how much work everything is. any help on how to not stress out anymore?