Is it normal that the more i try, the worse i do?

Here a bettr advice just relax boom dont read find your happy place and this will be risky but
Go and unfriend your best friend it'll feel sad 2 weeks man then say sorry or your friend is the one saying sorry in past weeks your best friend will be your enemy and you'll feel uncomfortable cant move easilly or feel lack of soace when hes ir her is around then say sirry for him at the test or etc important stuff then if youre best friends again you'll feel 2x confedent and stress free and happy and feel more ready for your exam then boom A+ i know it sounds bad but do it reply if it worked

Normally I'd say that maybe this is an anxiety issue... Trying really hard and stressing about it can definitely affect your performance. But you say that you have only felt very confident about these tests. (Perhaps you need to ask yourself if you're telling yourself you feel great about it, or if you really feel that way?)

The math part is pretty simple. I mean, you can either understand it and get it right, or you don't. So perhaps you need to just go over what you did wrong there.

The writing part is less simple, because writing is so much about the personal taste of the professor. I would ask the professor what you could have done better.