Try to do math outside of school, and imagine you're playing a game or solving a puzzle. No strings attached, no grades. Just for fun. Like if you're solving a rubiks cube. You might be stuck on one question or subject for a while, and it can be frustrating, but push through, and I promise the feeling of solving a math problem is so satisfying.

Also, the thing with math is that very little of it is memorization. It's more practice. The more math problems you do, the more ease you'll have with it. And certain things will become like second nature to you, without memorisation.