How to get better from being sick quickly.?

I've had an off and on fever for about the past week now, and a junky cough. I go to a boarding school, and I didn't tell anyone the first few days I had it because I didn't want to miss cl. But then it worse enough I finally told the dean and he sent me home. I've been home since tuesday(I think I've been sick since last thursday), and it's thursday right now. I already had to miss the PSAT and our Junior cl trip to Boston is coming up, and I really really don't want to miss that. I've getting lots of vitamin c and laying low as much as possible, but the fever still comes back... Any advice?