Believe to be misdiagnosed. Happening?

I went to the doctor some time ago, and was diagnosed with strep. Was given antibiotic to fight it, Dr said it may or may not work (I have a sensitivity to penicillin so It was something different) by the 15th, I still wasn't feeling well so I went back for a follow up where they gave me a shot of rosefrin, and different antibiotics. Today is the 19th, and I felt even worse so she advised me to go to the ER, to which I did. The doctor there seemed rather unsure of things, kept pausing and saying "umm" he tested me for mono, came back negative, And did a CBC. He then sent me home, saying to do my current antibiotic for another 24 hours, And if I don't feel better after that to switch to his prescription. I've been home since about 6 pm (it's currently 8:35) and my fever spiked up to 103.4. Should this still be happening?