chlamydia infection
"I was having a sharp burning sensation when I peed to the point where I dreaded going to the bathroom. 
A doctor visit later I had two 500mg pills. I took them on an empty stomach, ate pizza for lunch, and within a couple hours I found myself in the bathroom with very urgent need-to-go-now diarrhea. A few bouts with that over the next 24 hours or so, as well as having slight vision abnormalities while driving (kind of fuzzy, probably extremely dehydrated from the restroom trips), I was feeling pretty normal. The burning sensation subsided over the next week, slowly but surely. Looking back, I was uncomfortable for a day or so after taking the meds, but I can pee without wanting to jump out of my skin now. 10/10"