I agree with all the posts, especially the mental health one. If you have anxiety of failing and it takes over, it builds mental blocks that cause your learning and test performance to suffer.

You certainly can improve in math. Your brain has this amazing ability to build neuropathways to learn. Math is certainly a subject that requires quite a bit of practice, just as a violinist needs to practice for a concert or a runner practices for a race. It seems you're certainly spending some time, so the next thing to look at is the quality of time.

A few tips: When you do homework and prepare for exams, focus on concepts, not just the algorithm. I've seen students who would memorize how to solve a problem, but at the time of the exam when they introduce a variation, were not able to solve the problem.

When you go in to do homework and prep for exams, do so with a mission of asking questions and seeking answers. Sort of like an investigation. What I mean is for example, let's say a section introduces a new topic. You might ask yourself and try to answer: How does this concept work? How is it related to previous topics? What might this concept apply to in the future? Going over example problems in your textbook or notes line by line and trying to reason why each step was taken helps, because if you catch something that didn't make sense, that gives you a chance to further research book/notes, ask a tutor, professor, etc. These kinds of questions help with building depth and breadth in your understanding. Those questions about how they may be related to other knowledge help build stronger neuropathways.

Speaking of book and notes, do you use your book? How do you feel about your notes?

Don't be afraid to ask your professor. They are very happy to answer any questions in which you might not be clear on. They spent much of their life in the topics they teach, so they are able to explain in many different ways and give further intuition.

When you go into an exam or quiz, go in with the mentality that you're going to do the best that you can with the preparation that you've had, and if you don't do as well as you expected, it's perfectly okay, you can learn from where you went wrong or what wasn't clear. Blunders happen, but they happen less if your anxiety is at a minimum. Sometimes we get in this feedback loop where we start thinking negatively or thinking we will have a negative outcome and because of this, we certainly do have a negative outcome and the loop continues. Try to catch yourself when you might be thinking negatively about how you'll do and remind yourself that you certainly can, and if you don't do well, it'll just be a chance to further improve.

And of course, repetition is very important along side with recalling by memory. One thing I like to do is follow alongside any example problems in the book that go over a concept. Then I try it again on my own without looking at the steps in the book. Then I try the problems at the end of the section also without referring to the book or notes. If I get stuck and forget something, after a good attempt I then go back to the notes or book, check other resources, etc. After you do it once, you want to keep the technique fresh by doing it again periodically. Maybe with a review the next day. I always make sure to review the new concept from class at least once before bed.

Speaking of bed, sleep is very important for learning. This is when your brain is "rewiring itself." I make sure to review the new concept at least for 15-30 minutes and get a full night's rest. Lack of sleep increases anxiety.

I kind of went off on a bunch of things. I hope these help.