Well, you could have gonorrhea, chlamydia (not as likely, but possible) or NGU. NGU is any infection in your urethra that is caused by any bacteria that isn't gonorrhea.
It can be caused by normal mouth bacteria entering your urethra, strep if your partner had strep throat, viruses like adenovirus (causes upper respiratory infections), and a wide variety of others.
You really need to get tested. It's just a urine test, and make sure they look for white blood cells in your urine.
Let us know what happens.