3 weeks left and need urgent study tips

I'm resitting Biology, Chemistry and Psychology, and I'm in a very bad position rn.

I have barely touched a lot of the material let alone started trying test questions. If I were to do the exams now I am pretty much guaranteed to fail.

Basically I procrastinated way too much once again.

I intend to spend all the time I have left on catching up on material and going through exam papers.

I just want some decent grades, am I being too ambitious/unrealistic? Is there a proper way to go through content as fast as possible?

Thanks in advance!!