I've been sick for the past 2.5 weeks: nightly fevers, chills, strong headaches, muscle aches, and nausea.

I threw up around the second day and just threw up yesterday, but I think that time was dehydration-related. My doctor doesn't know what it is so he put me on a broad spectrum antibiotic twice per day about five days ago in case it is a bacterial infection. The progress has been pretty minimal. At times I feel perfectly fine, while at others, I feel absolutely horrible -- same symptoms: fever, headache, nausea, muscle aches... Not to mention, this antibiotic (Ceftin 500mg) really makes me nauseous. I'm not allergic to it, but is there any way to make the nausea go away? Or does anyone have an idea of what this illness may be? I really want to feel better soon! :( :( :(