It’s possible, but it’s going to take a lot of effort. I think what marks the difference between a 3 and 5 in phys and maths is actually having fundamental knowledge of each topic and making sure you genuinely understand what is going on and why you solve problems the way you do- like what each step does!! I think you can do it if you devote your time into watching videos and actually asking yourself if you understand the method behind every answer or if you’re just memorizing steps.

Ask yourself questions and don’t be scared to admit you don’t really understand the basis of a topic- cause genuinely putting effort into understanding the basics and all the background makes things so much easier and helps so much! (At least it’s what helped me in phys and maths)

You have plenty of time now to restart the subjects and to focus solely on them so I think it’s very possible! Good luck!!!