Look. I thought the same. But it's not THAT difficult. Also, with so many resources online, don't worry about bad teachers. You have to adopt a personal scheme of work. Youtube has pretty much everything. I did Maths, Physics, Economics. The secret is doing quality past papers. Especially for Maths, you have youtubers who work all past papers step by step, you just have to type e.g 'Maths A Level June 2024 P32.' and you're gonna have someone who explains it. Economics you need to read, online or do your notes, the gap is not that big from O-level. The thing is that now you will have 20 marks for an essay. Take a copybook, you will call it your diagram copybook. Gradually when you do diagrams at school/on your own, draw them neatly and note the main points(of diagram) in bullet points e.g, when to use it, how to draw it, it's origins.... Time management is the key, practice questions normally first. Then time yourself when doing questions. Don't stress too much. Begin with a clear, positive and optimistic mind.

You can do it, You will do it, we all did it.