One word: PRIORITISE!
I may not be the most organised person here but I try so ill give you a few tips and hopefully they'll help
Most important thing I find is keeping a diary, it may sound stupid and lame but honestly it helps tremendously. As soon as I get any homework or notifications for any assessments I write when they're due down in my diary so I have a constant reminder.
Now having said that when I come home, I do work according to two main things 1) when its due 2) how important it is
So for example if youve got to research something for English which is due on Tuesday but you've got a maths test on Wednesday, youd obviously want to put more time into the subject that you will need helo in most ( which would be maths in your case)
Also I find keeping a checklisk of what you have to do every night also helps to keep you motivated and on track.
It may sound crazy but doing things ahead of time can be hugely beneficial too, like I know my first assessment this term is for chem so ive already begun making notes in order to be less burdened when the time for the exam nears.
It shouldn't be taking you till 10 to study every night, are you sure youre effectively using your time? I.e. time spent studying > time spent procrastinating? Its completely fine if you arent, we're all guilty of it. Just make a routine for yourself, study in blocks and have periodic breaks in between>> moderation is key!
As for maths, I know them feels bro! You're doing fine now but if you want to improve one thing I can tell you is practice, not just the homework you get set but extra questions and exams on top of that, if you dont understand a question Highlight it and go to your teacher in or out of class time to help you, trust me they'll love you for showing initiative. If you still dont see improvement consider getting a private tutor just to help push you
And most importantly, CALM DOWN and enjoy your last year in high school !