There is no better way to catch up, then actually doing the homework. I spend more time, avoiding the homework, then actually doing it. Imagine that!
I have to put away all games and distractions and resolve to do the work. I never really want to, but have to make myself. My suggestion is resolve to do the homework, promise yourself, and do it.
Ask your teachers if you could come in at lunch or after school. And if you are behind on credits maybe your school does online classes, you can ask your counselor if you could make up those classes that you failed. And you can ask to retake test that you failed or didn't get a good score on.