Actually, you don't have to panic. By the third grade, all the questions and even the contents were clear (at least in my city). You can specialize in those questions to be tested. I mean, according to the present situation, you don't need to get good grades, as long as you can get in.
Of course, I don't advocate this practice, but I still hope that you can do more topics and improve your math ability in an all-round way, because you will naturally understand something if you do more. Mathematics is a comprehensive subject, and junior high school mathematics is actually not difficult. You should be confident to take the exam.
It would be better if we could have a good math teacher. He can teach you, so you can get a tutor. It's okay to leave college. He is closer to you than a graduate student and will do better in the exam. Also, prepare a wrong question book from now on, if you don't write it down, turn it over if you have nothing to do. Even if you don't turn it over, it's good.
That's all. I am an opportunistic person. I still hope you can play slowly. It is still early. Don't panic.