My teachers say I'm struggling in mostly chemistry, physics and biology. If don't work harder I'll be dropped to do the foundation paper on my mocks in June. They didn't actually give me any help just gave me more work on top of what I'm already struggling on. I find it extremely hard to keep up. It all feels like such a big jump from last year. My target grades are all 8's but I'll never get that at this rate. Any advice on revising?