Why do i hate school and my life?

OK so heres the deal: i'm in 10th grade, and right now have a 2.8 gpa. a lot is due to my constant absences from chronic migraines, but a lot i just fake. i hate school more than anything in the world. I need to get a B average to get a car, which i need to get to soccer practice. Playing soccer and smoking weed are my only solace from hating my life, but now they're barley working.. I can never just let go. Whenever i talk to my parents, its about getting a B average, but i just can't manage it. Last semester i gave everything i reasonably could. every day after school i went to the library and did work, then went to soccer, then came home and did more work. this resulted in getting a 2.8 gpa. I just don't understand what this feeling is. I can't stand doing this work, it just feels like such a waste of life. I understand that we have to do things that suck in life, but i just can't do it anymore. I have no idea what happened, from kindergarten to 8th grade i didn't try at all, and the worst grade i ever got was B- on a report card, and the rest were A's. Now in highschool, even wen i give it the best i can reasonably manage i can't get good grades. I just wake up every morning and absolutely hate my life because of school, and then I am forced to exert the majority of life to school work which all seems so useless, and then when i do it, it doesn't even pay off cuz i still suck. I have no social problems at all, and love all my friends, but school is just making it so i have no joy in life. I'm over emotional, resent my parents and my teachers, and just f*ckin hate waking up every morning.. WHAT SHOULD I DO!!!!