I am flattered you think of me this way, little one.
I suppose I could try to help. Back when I was still a teenager/young-adult, around 16-17, I remember the most efficient method I had for studying was researching and practicing the subjects I had the most dificulty on.
For example, biology has always been a very difficult subject for me. I just couldn't learn anything during my classes, because it never really caught my interest; so I spent hours and hours in the school library just reading about it and taking notes. Of course, this can be quite tiring, especially if it's about a subject you don't like, but once I figured the complicated stuff out, biology has actually become a subject I like to this day. So maybe if you tried to follow this method, "going from the corners", you could have a successfull study routine. Read, take notes, practice, do research, everything helps. But do it on your own time, or else you might become overwhelmed and shut down from wanting to study. Trust me, I have been through that.
And the advice I can give you, dear, is to take your time and keep your hopes up. You should not be afraid of failing your exams, you should be focusing on trying your best. Your effort won't go unnoticed, even if your grade ends up being low. Trust me when I say: it'll pass.
Thank you for your question and for reaching out for help. Do know that I am proud of your determination for wanting to learn how to study. You can do it, little one. ⁠♡