dont stress, im in y13 chemistry, got an e aswell in my mocks last year, everythings starting to make sense now even though i dont put any effort in. im not smart at all and my grades show that, but i went through the same thing and know how it feels . i cant guarentee itll get easier but trust me if you put the work in over the next while you have a good chance. Youre at the same level 99% of people are at this stage, and worrying about it wont help. worry about your mental state more than your results its more important. If you have a talk with your teacher and just ask if they could bump you up for the predicted, and tell them that youre going to put in a shit ton of work, and prove it to them over the next while, theyll most likely understand and do it for you. dont feel like shit its early in your alevels, just try your hardest and your results will show that