High School Help

To me, school has gotten to the point where I dread it practically everyday, and whenever I'm doing homework I don't really care whether it's correct or not I just want it done. And I'm slacking a lot on making sure I'm studying and just having good school related work-ethic. I'm trying to get back on track so I can catch my grades before they get any lower, but whenever I try I just get so stressed out on work, and it's not because it's hard, I just have no motivation. How can I snap out of this?