How do I deal with impossible amounts of homework?

My math and physics courses are bombarding me with impossible amounts of ignments. I can't do them all because I don't have time. What I have done up to now is what has kept me from falling below 60s and 50s in my courses yet I do exceptionally well on the tests. Now the ignment deadline is 3 days away along with my exams a week later. Now my english course decides to ign 2 major papers. This is making me abolutely miserable and I strongly feel failing a course would destroy me mentally because all of it would be for nothing.