I Was In The Hospital Due To Gall Bladder Pain..

I was in the hospital due to gall bladder pain.. I was given antibiotics for my 5-6 day stay before getting my gall bladder removed.. 5 day after discharge I develop thrush. I went to my one week check up yesterday and the doctor scared me by saying I should get tested for H.I.V.. I only had a small pain for the first day and only when I brushed my tongue. How high r my probabilities that this episode is antibiotic uses related? I've never had thrush in my 33 years.