Keep revising. Basic formulas. Dont read much now. Just stop reading new things. Give mocks. The score doesn't matter. Just try to improve. There is no magic button. Give mocks daily.. keep revising the formulas. The actual Bitsat will be easier than any mock.
Exam stress is natural.. just dont over do it. Its just an exam. Life is more than just an exam. I am going to see Avengers Endgame for the third time today. To me.. experiencing that is life. Studies are there just for providing me. I love movies, sports, tv shows.. vacations. Why stress over a thing that is beyong your control now.
Think of the mistakes you made(we all make them) and know that you did the best with the time you had in the end. Try not to repeat such mistakes. Life gives you many opportunities. You will realise than when you join college.
Just chill. Dont take stress. Everything will fit exactly eventually. Not because of some god... or luck... its because you worked hard and you earned it.