I Came Back From Mexico, Got Run Down And Became

I came back from Mexico, got run down and became sick with my usual sore throats. Tonsils swollen, uvula beyond sore and red and sideways, and off and on fevers. Been on erythromycin 3 times in 3 months and still no luck. Negative for strept and mono. Had blood work done. What is wrong with me? I have read that I could maybe have uvilitis just from the internet what I have learnt and read.