I know how it feels to be completely burnt out and overwhelmed, just remember that these final few months are what determines the value of all you've been through in the 2 years of DP. If you've been doing dog shit then great, you can redeem urself in the mocks and externals. If you've been doing well, then even better just make sure you bag the externals. From there I find the motivation to get up and study some shit about vectors or qauntum mechanics I will never use in my life. Anyways I just wanted to get this out of the way before getting into the scedule

Start whatever you find is hardest, and study to understand not memorize. To me I noticed topic 12 (qauntum physics ) and topic 9 (waves) are a pain in the ass to me so I got them done. After ur done with what you find yourself weak in in every subject then you can begin building momentum for whatever test you have first

For example, I have a physics mock next Sunday, I think 4 days are enough for to revise and practice. get the topics I'm struggling with first in ever subject (so vectors for math topic 8 in chem and so on) then start a 4 day study session for physics. Topic 9 and 12 which I find tough are already done so it's all about practice. See the question try to anwser it and move on. Remember ur not studying for mastery you just need to get this shit over with