I need urgent help ):

As someone who got through highschool and college here is what I recommend:

Try rewriting notes, rewrite them but summarize them in your own words. This will engrain it in your brain and makes you really think about what you are learning. Putting it in your own words as well makes you build upon what you are learning indirectly because you will build upon it naturally. 

For example it could be, "Susie sold lemonade at her lemonade stand, this lemonade stand was located on Fear Street. Her lemonade was $1 a cup, and she sold 100 cups of lemonade. Susie made $100 in sales that day from her lemonade stand." You would rewrite it as, "Susie had a lemonade stand on Fear Street and made $100 in sales selling lemonade for $1 a cup".

(im not in that year,but this gets me pretty good results)

read over source material,flip it/close it,repeat what i can from memory,read over original,jot down weak points,revise sheet of paper with weak points,then repeat everything you can from memory because you don't want to forget the stuff you're good at by focusing too much on the weak points,idk if that explained it well but repeating stuff aloud helps for some reason.

i know this has been said like a billion times over but studying consistently helps a fuck ton. i built a system where i focus on more science subjects during week days, and humanities on the weekends. basically, when you get back home from school you revise everything you learnt and then focus on the subjects you decide to study that day