Hi Milo. I'm with Aaron, here: that's way too much studying. You say you sleep a lot now, I don't think two hours (or less??) each night will be fun or helpful. For reference, I study around 5 hours (which I already think is a bit excessive) each day, and your plan adds up to nearly 12, with no real breaks. While I don't think studying is meant to be fun, necessarily, I don't think it should kill you either.
Instead of using hours to measure how much you get done, why not use a to-do list? Using things to keep track of how many things you get done is a lot more rewarding imo. For studying, I think it's good to write one on a sunday night for the week, then one each night to plan the next day. Alternatively, a system like
pomodoro (25 minutes on a task, 5 minutes off three times then a longer break) is also very good and will help with working in timed conditions. Most people aim for 10 rounds but obviously if you're going hard on your studies you're likely to do more.
example to-do list
- Notes for chapter 1 methods
- Notes for one poem
- write an essay plan for that poem
- spend 20 minutes typing* notes from workbook
- etc., etc.
* I prefer to type my notes because then if I forget to take them with me I can still access them, but obviously for classes like maths it's a little less convenient to type them. Writing them neatly in a new book works just as well.
I'm an afternoon sleeper, too. I can't function through the whole day if I don't go to bed when I get home from school. It got pretty out of hand earlier this year because I was so conked when I got home I kept sleeping through dinner and into the next day, every day of the week (consequently neglecting chores, study, any social interaction at all, etc. My folks weren't happy

). This kind of crazy oversleeping obviously isn't very healthy so I went and talked to my doctor about it; he made me get a blood test to make sure I wasn't dying (took like 6 vials tbh I thought I was going to die from blood loss). Part of the issue was a vitamin D/iron deficiency, which are surprisingly really common, and getting on some sweet OTCs pretty much fixed everything. Other contributing factors to excessive sleep could include depression, poor diet (like not eating breakfast, or not taking lunch to school because you're lazy) or just not getting enough sleep when you're meant to. If your sleeping habits are seriously out of hand, legit go talk to a doctor. Best case is there's nothing wrong, worst case is you find out what's wrong. Sleep is really important and can mess you up if you don't get it right.
If your school hasn't finished the course, don't worry about getting ahead right now. Focus on getting ready for your SACs because they're the most immediately important thing coming up. Do your revision next; forgotten how odd and even functions work? That's more important than a practice exam because what if it's on the exam? There's not a lot of point in doing exams if you're not ready for them. Same with lit (and other essay classes?). Don't bother with writing an exam style piece until you know what you're doing. I'm not doing poems but it's easy enough to read one and just write everything you think about it; it doesn't have to be pretty and academic, you could write "oh and that part with the flower seemed important but I don't understand the significance yet; this one doesn't rhyme and I didn't pick up on any rhythm, maybe I should read it out loud next time?". It gives you some direction for your research instead of mindlessly looking up obscure facts about Seamus Heaney's life and hoping they'll be useful, or that you'll remember them. As a side note, I don't think writing notes for methods is very important. Unless something's changed since I last heard, you can just bring your textbook in and you're better off doing practice questions. There's also some great notes around here.
If you're worried about your studies, AN's pretty much the best place you can be. Don't be afraid to ask questions - everyone here is super helpful and there's literally nothing to lose. Feel free to PM me your lit work (or post it somewhere here) if you'd like some help or secondary opinions. But seriously, talk to someone. I can nearly guarantee that the staff at your school deals with stressed out students every year and they can probably give some better and more specific advice.