I (male) had an encounter with a professional (female) 25 days ago. I received unprotected oral and analingus. She performed a vigorous prostate massage. Then we had penetrative vaginal sex during which the condom slipped off and she stopped when she noticed.

Day 11 I had urinary difficulty and pelvic pain. Day 12 I went to urgent care to test. Doctor said wait for results. I felt sicker hours later. Did a sketchy telehealth, got prescription for Cefixime (800mg) Azithromycin (1000mg) and Metronidazole (1000mg). I took them all as directed. Symptoms waned over 72 hours, urine stream returned to strength, though residual aches and feverishness remain thirteen days later.

Day 12 urine tests came back negative for everything, even UTI. However the doctor made me do a "clean catch" sample and I am pretty sure I peed an hour before. Could it be false negative?

I also took an HIV RNA test on Day 12. It came back negative. That's good, yes?

After taking the antibiotics I had bad diarrhea. The diarrhea was mucusy. No discharge from penis.

Did I take the wrong pills? Might I have something anal? How soon could I retest for Chlamydia / Gono? Might it be HSV2? (I had a pretty bad itch for a couple days, though it faded. No rash. Been HSV1+ since college at least.) 

Or did the dominatrix over-dominate my prostate? I'd never had that kind of experience before. I have hemorrhoids and they bled bright red the night after. Maybe I got an infection? Does that happen often?

And am I right to not be too worried about HIV?

I appreciate any help you can offer. Consider me a big fan.

Your symptoms are not typical for any STI:  they started too late to be due to gonorrhea; and they are not typical for gonorrhea, chlamydia, or nongonococcal urethritis. However, they are perfect for either a non-STI urinary tract infection or a prostate problem. And it sounds like that's how your doctors (maybe a urologist by telehealth?) felt about it. So I am inclined to agree that the vigorous prostate massage might be the cause. Perhaps you had minor prostatitis before the sexual exposure that became more inflamed.

Having urinated an hour before the clean catch specimen cannot turn an otherwise positive UTI culture negative. But this is something to discuss with your doctor as well. The treatments you took sound exactly right for prostatitis. At this point, there is no need to test again for gonorrhea or chlamydia; those tests already were conclusive, and in any case having taken the antibiotics would make the results negative even if you had any of these beforehand. HSV2 is not a possible explanation for any of this.

You also are right not to be worried about HIV:  it is very unlikely your partner has HIV, and even if she did, the chance of infection is under one in 2,000 for a single episode of unprotected vaginal sex.

In summary, I doubt this was an STI problem of any kind. If your symptoms continue or return, my advice would be to see a urologist in person. In the meantime, I hope these comments are helpful.

HHH, MD