Hi Sahil,

If your Physics is weak, I will recommend you to opt for a personal tutor who is specialised and have a great approach. 

Doing this will help you to enhance your physics knowledge and base.

For chemistry you can go there and can take the classes. Physics need practice so if you do practice all the time with personal guidance from a tutor then you will able to focus more and give more.

I hope this information helps.

All the best.