How to revise for Physics, Chemistry and Maths? WJEC (Science) Maths (OCR MEI)

Hi!

I'm desperate and need help with these subjects, especially Physics. I revise from the revision guides I've bought and nothing seems to be going in - I really don't find these books useful at all.
Does anyone have any methods? Recommended revision books or websites that would be a massive help.

My main focus has ben Chemistry and Maths and because I've struggled with Physics, I've started given up on it but that was the worst thing to do as I am scared I'm going to fail now. I desperately need to pull my weight and ensure that I can at least get a C on the paper.
Anything you recommend or say would be a massive help to me right now.

Thank you so much!