What should I do about this problem? I really need help.?

I see no problem so relax and be cool. Nothing in school should ever cause you to think about hurting yourself, and definitely not suicide. There is a great future for you, so be prepared if she wants to talk. Talking doesn't hurt, just grow thick skin (idiom) and don't let her bother you so much. Just apply yourself and do the best you can. Try not to lie next time though, that just causes problems and make people not trust you.