hey guys. so i just had unprotected sex with a friend (we're not a couple) 3 days ago, he cummed a bit inside of me but immediately wiped it with tissue, then I went to the toilet and peed, note: it was already sore when I peed.

after 3 days, the peeing still hurts and in the day i would get a yellow discharge, that I have to wear pantyliners for it, not much but it's visible. 

I'm not sexually active my last sexual activity was august 2016 with the same guy. But this friend of mine likes to play around with girls (he told me that he hooked up with other girls after me)

I just want to be sure though. Help??