How can I get away from the stress of school right now?

the third term is closing, I have B's in most cles, some C's I need to bring up, and this closing week is filled with tests. I don't even know what organelles are in science, and I had to give the teacher my notebook and papers for grading the whole weekend. we have an english quiz on prepositional phrases and adjective questions and adverb questions, I barely made a B on my last one exactly like this one, and if I don't do well, I get a C in that cl. I have a C+ I need to bring up but I don't even know if I can if I get an A on a quiz.. I have a math quiz tomorrow and I don't even know the ignment due to my absence that period. not to mention that I have hours of homework ahead of me..... how can I relieve this horrible stress?!