If you make a really big effort to catch up then you may find that you hate lessons more which could make them more interesting? If you can drop out of subjects then get rid of the ones you find the hardest and you will have more time for the subjects you have left. I would suggest getting yourself more organised so that you keep on top of all your work in future, for now just give it another try, make sure that you reward yourself in some way when you do your work which should help you to stay motivated