It is difficult for you to improve your situation. There is no regret medicine in the world. If you think there is a shortcut, what are those who work hard for?

My advice to you is: don't do other questions, just read the textbook. After reading a section, do the after-class questions. You must finish them by yourself. If you really can't answer, ask your classmates and teachers. Don't be embarrassed to ask. You will suffer.

You don't have to do difficult questions now, just understand the basic content! You should know how to give up in the exam. If you can't do it, jump, but don't jump all the questions. Mathematics is actually very simple, and basic understanding is very easy.