Ok. I do those same subjects as you aswell.
I know where you're coming from,
but Biology has ALOT of content so I would start being realistic. If you want an A grade, revision should really start from now.
In terms of Maths, maybe not so much revision required, but more practise than anything. The same with Chemistry.
Don't waste your time so that you'll look back at this in a few years time and wonder why you didn't utilise your time properly, the more revision the better.
2 months however is a long time to buckle down and do some proper work. So don't stress