Sorry that you are feeling poorly. My 15 year old daughter is in the same boat. She had Mono in the fall of 2007. This winter 2008, she would feel poorly, get better, feel poorly again. This happened more times than I care to remember. Finally she was diagnosed with Mono again, in January of 2009. She got better on several occasions and returned to school, but once again would become sick. Low grade fever, sore throat, fatiqued, stomach ache, and bad headaches. She also began to have problems
with her jaw clicking, and eventually partially locking so she couldn't get it open all the way, TMJ syndrome. I think this was brought on by all the stress of the mono. I have taken her out of school indefinately with a tutor coming daily. She continues to remain fatiqued, and just feels blah. We are seeing an infectious disease Dr. at Mass General Hospital this Friday. I should know more then.

Thanks for the reply! I'm sorry about your daughter. It's actually looking like it isn't mono, but I was convinced earlier that it was. Right now, they think the last bout of illness was a sinus infection, but they still have no way of explaining the other fevers/stomach problems. We're just going with the idea that I got knocked out several times with different infections. If something else comes along, though, I don't know how quickly I'll be able to bounce back.
They tried to test my blood, but they were unable to draw blood from either arm because my veins are small and hard to find. So they sent me home with sinus infection antibiotics. I'm starting to feel a bit better. I hope that's what it is.
I hope your daughter feels better soon, and thanks again!