So you received oral sex. Receiving oral sex is very low risk for std's. Here's an answer describing a similar situation from a guru in std's, expert Dr. Hook. He's pretty infamous in the world of sexually acquired diseases. https://www.medhelp.org/posts/STDs/STD-from-receiving-oral-sex/show/1988650 You
can read his explanation of why biologically it is unlikely to result in an STD to receive oral sex. He states that chlamydia is not going to be a concern through receiving oral sex. Gonorrhea is a tiny risk and nongonococcal urethritis (NGU) as well. A three day course of antiotics is very short and given for a very mild situation. That you aren't better, I'd check back in with your doctor. Was your testing for std's done at the appropriate time frame post exposure? I would ask your doctor regarding the antibiotic and the std testing you had. It 'can' interfere. But really, receiving oral sex is a very low risk.