You did nothing wrong at all, I am only 15 and probably can't help but if there is anything I can do to help you understand anything please let me know. And also I also struggle in school and I'm okay so I bet you will be okay too. Also, you are more than your grades, and I know it sounds so scary now, but you'll be able to do this. You are so much more than the grades on a paper, you are a whole amazing human being. But I struggle too and I was able to beat it, I am sure with enough effort you can overcome this big obstacle, whether you must climb through it or go over it or under it, or right through it, I believe in your ability to totally smash it. I believe in you. And I also send hugs. Good luck!