Have you spoken to your dr about this or the nurse or the assistant, that would be my suggestion.
Hope you get to feeling better!

I have the same problem. I fell sick in early december, I had a bone crushing amount of fatigue coupled with the worst never-ending headaches centered at the back of my head. It took the doctors 5 months to figure out I had mono! It's now june, the headaches and fatigue are better thank god, but I still experience severe bouts of sickness and am still not able to work! Hope you're doing better!