Heya! I'm sorry to hear you don't have a lot of motivation, I totally feel the same. What I find helps me is to have a list of three goals to achieve for the day, they can be school-related or even wellbeing/chore related, for example:
- Finish draft for English
- Do dishwasher
- Write two paragraphs of Ancient history assessment
The clearer your goals are, the better! Also, something I find helpful is the longer you work, the longer breaks you have. For example, work for an hour and then take an hour break. Equal gains = equal rewards! Hope this helps and best of luck!