the rabbit

ok....i'm a 22 year old male, and i ended up getting drunk and having unprotected sex with an older woman whom i had met at a bar that night. the condoms she had wouldn't fit me, but she swore to me that she was completely std free, saying she used to work in a medical facility and got tested on a regular basis. so i went ahead and had unprotected sex.this was just a one night thing, and everything seemed fine, but about a week later i noticed that the tip of my penis had a slight, pinching, tingly feeling near the opening of my urethra. it doesn't burn when i urinate, and i see no discoloration or cloudiness in my urine, but i'm still scared!! i have also been noticing a slight shooting pain in my groin near my femoral arteries!! i was wondering if anybody knew what this might be, if anything, or if it's just my mind playing tricks on me for thinking about how i had unprotected sex and regreting it. i plan on getting tested to be sure, but i would like some opinions on what this might be.