It may be the flu - i suffer from allaergies and last year teh same thing happened to me - i was sick for about 2 months because once i got over one thing it turned into something else i had the flu, then an upper respiratory infection and then i got vertigo!
I know it doenst sound like much comapred to the otehr antibiotics you are taking but theraflu helps ALOT (the one you drink) and if anything it will at least soothe the pain and let you sleep.