I AM SO FREAKING FRUSTURATED?!?!?!?!?!?!?

I can't stand it. I stay after school before tests and quizzes and even when I don't have test or quizzes, I do all my homework, and I still get D's on my midterm and marking period grades. I'm so frusturated because I know I study twice as hard as many people in my cles and yet they get A's!!!!! I'm NEVER going to get accepted in college and my moms gonna get so mad at me and now I'm literally in tears. What should I do?!!