Be relaxed ! It happens with almost everyone. Good thing is that you will be able to master mathematics soon if you just work on it. Here's how-
For improving your mathematics read all the examples first and all the formulas very carefully and only then go for the exercise. It will be better if you solve the exercise after about an hour of reading the examples and formulas.
Practice it more and more, and must see the examples, your mathematics will be improved very soon.
ALL THE BEST