Most commercial sex workers do not have STIs, even if your CSW partner had an STI, most exposures to infected partners do not lead to
infection, and oral sex is particularly unlikely to lead to
infection, causing primarily NGU or, more rarely, gonorrhea in exposed persons.
Your symptoms do not line up particularly well with STIs either. Typically the symptoms of STIs acquired from receipt of oral sex are burning during (not after) urination which is present continuously, not intermittently.