Hii! As someone who did these tests, don’t stress out too much, it seems from what you said that you tend to stress out over the answers, and if you stress out too much then you will start doubting yourself. As for the silly mistakes, I have made so many, especially with calculations as well, but what matters is what is your silly mistake and working on how to correct it. For me I just did lots and lots of practice calculation questions, because soon after much practice you will see that some questions are similar in terms of what they are asking, and it will become second nature to you. With memorisation, maybe try Anki, Quizlet or some form of active recall, as they will be retained much better in your head. Again, don’t worry too much, i’m sure you worked hard and revised a lot so believe in yourself that you can do it.
I hope this helped and let me know if you have any more questions.