bahh! hopefully you guys are still doing well! It has been sometime!
If u want to go jc (science stream in particular), Amath and Chem is a must. If u can afford, go for tuition. Personally i got a tutor (Amath and Emath) who help me improve from 20++ to 70+ and 80+ in 4 months. His way of teaching simplifies the subject, however i still had to grind f or a period of time.
I guess it depends on how determine u are to catch up with ur grades and how much you can understand from the tutor.