What's wrong with me, I'm still sick?

I've been sick for a while with a sore throat, cough that produces phlegm, congestion, headache, fever, fatigue, nausea, and pain in my chest when I breathe deeply. I went to the doctor again on Tuesday and he thought I had mono. My lab results came back normal. I had to get a Rocephin shot on Tuesday, Wednesday and Thursday, but they haven't helped me at all...in fact, my leg has been tingly and numb feeling since my last shot. Does anyone know what's wrong with me? I've tried antibiotics, prednisone and cough syrup. I can't miss more work.