the left upper abdomen is the location of the spleen and splenic enlargement is common with mono. if you were tested for strep (rapid strep test or culture) then your diagnosis was probably accurate but if the medical provider just looked at the throat and pronounced that you have strep then there is a 50% chance your original diagnosis was about as accurate as a coin toss. ask for a mono test (ebv panel) and get that abdomen properly examined.
when to see a doctor? strep two weeks ago treated again. now severe pain in left abdomen? mono?