Pain Urinating (male) for 24hours, not UTI but STI?

Hi all, I may have (foolishly) had unprotected sex 5/6 weeks ago with a new partner. I've no idea if I used a condom or not but my mind is going crazy cause I have a serious gf. Feel very ashamed. That night I was so blind drunk that nothing happened and it was a forgettable experience for her. Not sure I even had sex with her. Anyway, last Sunday I had pain whilst urinating which lasted for 24 hours. My initial thoughts was a UTI but then now I'm thinking STI. I submitted a urine sample to my doctor surgery expecting the bare minimum UTI / STI check. The results were Standard for my urine sample and they hadn't checked for STI. I plan to get checked as soon as possible but because I don't have any symptoms I have to wait 3 weeks. Or perhaps I do have symptoms??? Currently 5 days later I am fine. I understand there will be no clear answer until I have the test done. QUESTION Basically my question is, If I have Chlamydia... how long would the pain whilst urinating (in penis) last for? Would it normally only stop once I took antibiotics? Thanks,