I am a senior high school math teacher in a provincial key middle school. I have some suggestions for your question:
1. Adjust your mentality: Mathematics is really not so terrible, it is your subjective consciousness that magnifies the difficulty of mathematics, so the first thing you have to do is to adjust your mentality first and despise it strategically! I believe I can learn well and build up good self-confidence.
2. Tactically, active learning is much better than passive learning. We should be brave enough to face mathematics tutorials and exercises, dare to try and challenge, take the initiative to preview and review in time, and initially realize the sense of accomplishment in learning mathematics, so as to cultivate our interest and enthusiasm in learning.
Some of your worries are unnecessary. In the third year of high school, you will review and consolidate all the knowledge you have learned comprehensively and systematically. As long as you listen carefully in this link and solve the remaining problems in time, you will certainly be able to keep up, with the focus on solving the middle and low-grade problems. Giving up difficult problems is also an art.
Then, if you have any questions, you should discuss and consult with your classmates or find a teacher in time. It is also very beneficial to exchange some methods, skills and experiences in learning mathematics.
In short, as long as you have the heart, as long as you want to change the status quo, as long as you act, you can make continuous progress and surpass yourself! Xin Angxin, you can do great! Come on!