Re: I'm worried about starting school.
When I was in highschool, we had a study hall elective. It basically was an hour to get homework done. If you're school offers one of these, talk with them to see if you can use that time to take a nap. Maybe you're dr can write a note that sometimes you'll need to lay down during the day. Even if you can get 30 minutes of quiet time, that might help your concentration. I would also have your Mom talk with your teachers and principal.
Make sure you're taking a good multivitamin and get to bed early every night. Hang in there, things are going to start getting better. I just started abx a month ago so I understand how yucky you feel right now.
Just FYI...when I was a kid, I had chronic pnuemonia and wasn't able to participate in gym....the stupid gym teacher still gave me a low grade!! Just make sure that your gym teacher won't mess up your grades since you're not able to participate most of the time.