So try your best with what you have left.
Whatever you get is what you could’ve gotten. You shouldn’t worry about things you can’t control.
If you’ve put in your full effort and still not achieved what you want, there is nothing to regret.
fair enough, 3 weeks is a lot of time and you can do this. Remember your finals are much more important than this shitty forum and will decide the rest of your life, good luck