I'm not sure, but I think you are having trouble performing because you are stressed and this feels like "everything". If you can take a deep breath, take a day off and get a good night's sleep, that may help. Tackle the English class, know you will make mistakes, but you just have to pass and move on. It feels like a lot, but there is so much ahead in life - try to just be present, work through these silly school courses (they are, in the scheme of things, silly), and do whatever you need to do to stay calm and relaxed - you are more than capable, but this is a stressful time, and that makes it hard to think clearly. It will be okay, though.