painful mystery

About a month ago i had unprotected sex with a girl who apparently gets around.
About 3 days later i starting having symptoms with my penis, I was having a stinging pain in the head of my penis. I went to my family physician because i wanted to get an STD test, for some reason i couldn't get him to just give me a test he only did a urine analysis for chlamydia and gonorrhea, as well as gave me a shot in my hip and gave me some antibiotics to cure them in case the sample came back positive.
So i was confident i was cured but the next day i started showing symptoms again, I waited about a week and then i went back and told him my symptoms still remained. He gave me a weeks worth of more antibiotics and told me to come back in 10 days if it wasn't completely better. I noticed a few different symptoms, the tip to about half way down the head of my penis turned slightly red and was extremely sensitive. It begins to hurt when i have to urinate, when it rubs against the inside of my boxers and when i get an erection. I'm going to go back to my physician in a few days if it persists but i have the feeling he isn't going to help me out, he doesn't seem very competent. If this sounds familiar to anyone PLEASE help me out.