year 10

so ive been in year 10 for about 5 months now but something that im struggling with is time management

when i was in year 9, i would get like 80-90% on basically every single test because i had more time on my hands. Now that im in year 10, ive found myself revising for tests the day or two before, doing my homework at break, having more tests to revise for etc. like my grades havent been terrible everytime i revise for a test the day or 2 before (eg. In my comp science test i revised for 2 days before i got a 9 but in the chem test i revised for a day or 2 before i got like 78%) … my scores arent low but my time is managed terribly and i dont sleep enough and sometimes i could walk into tests worried bc i hardly revised for them. If snyone has any advice on how i can manage my time it would be much appreciated

Also because i feel like year 9 is a transition into gcse year but all they did was teach us some gcse content but they didnt increase the number of homework we’d have or the number of tests we could have a week so when i got into year 10 i had no idea how to manage my time since i could have like 3 big tests in one week

Helpp
Thx