I do know that severe sinus infections can cause flu like symptoms, and people also have reactions to many kinds of medicines. Maybe it's one or the other? Although I'm betting on the first. Either way, the doctor would be your best bet at this point.
Remember, when taking antibiotics, all of the good and bad bacteria are being killed off inside of your body. If you can stand it, take raw garlic during and after the round of antibiotics. Crush one clove daily and let it sit for 10 minutes, and take it with milk or something that will soothe your stomach and stop the burning. The garlic kills off a lot of the bad bacteria, while leaving the good. Thus giving your gut the ability to populate it's self properly.
I forgot to mention I have also been having fever like cold sweats at night