It is unlikely you have (or had) gonorrhea, chlamydia, or other STI your symptoms don't fit well; oral sex is low risk (although not zero risk) for STIs that cause urethral infection; and condoms are very effective in preventing such infections by vaginal sex.  I doubt you have (or have had) a UTI either. I have to wonder why your doctor prescribed an antibiotic based on your history and the negative urine dipstick result. However, it probably did not affect your STI test (presumably for chlamydia and gonorrhea) only 2 days later. (It takes several days for the current standard tests to become negative with effective treatment.) 

Those comments partly address your questions, but to assure no misunderstanding:

1) How much risk? Very low, as discussed above.

2) Since you probably were not infected, it is unlikely you put your partner at risk. This also depends on what antibiotic you took for 3 days. If active against gonorrhea and chlamydia, that would further lower any chance you could have infected her. What antibiotic was it?

3) Negative urine leukocytes is reassuring, although in itself does not conclusively exclude gonorrhea, chlamydia, or nongonococcal urethritis (NGU).

4) Your test result probably was reliable despinte the antibiotic.

5) I'm a bit confused by your description of the "burning sensation". What do you mean by the "top" of your urethra? Was it urethral or penile pain? When urinating or continuous? and you never saw visible discharge, right?

6) I'm confused by your statement about azithromycin. Is that what was used for the possible UTI? Or was this in addition to that treatment. What dose of azithro, and what exactly was the timing?

I may have more to say when you fill in the missing information. In the meantime, I hope these comments are helpful.

HHH, MD

Thanks for replying. The pain I’m feeling is near the top of the penis inside. No sign of discharge it has easy quiet a lot now. I would have to come trays on the pain to notice it.

The antibiotics I was taking was Trimoptin inside for the assumed UTI. I had taking two days of the antibiotic before I did a urine test for STI. Reason I went back to test was the pain did not fully go away. 

If the pain was in your urethra, "toP or elsewhere doesn't matter. The timing is consistent with inflammation related to the sexual exposure, but clearly you had no traditional STD. Herpes due to HSV1 is possible but unlikely:  urethral herpes usually is much more painful than you seem to have experienced (I've had patients who described it as the worst pain they ever had), and usually there would be herpetic lesion on the outisde of the penis (blisters, sores, etc). Adenovirus, a common cold virus, sometimes is transmitted to the urethra by oral sex, so that's also a possibility.

At this point, I suggest sitting tight. Absolutely no more antibiotic treatment of any kind. Your symptoms are improving and probably will clear up entirely, and it is unlikely you have any lasting problem that will harm you or any futhre sex partners.

Yes I’m referring to the azithromycin for gonorrhea, chlamydia. I didn’t pressure him for antibiotics I didn’t even mention them. He said he was going to treat me for both gonorrhea, chlamydia, 

Also when I received the oral from my partner this was 5 days after the incident she had just finnished a perception for a UTI about 3 to 4 days beforehand. Don’t know if any of this is relevant 

If you really have true cold sores, that's good:  it means you are immune to a new infection with HSV1, the virus type that causes oral herpes -- and therefore your symptoms cannot be herpes from this event.

The most important question you ask now is "Would it be safe to assume I didn't have an STI?"   Yes, that's safe. Of course I can't guarantee it, but from all you have said, any STI is very unlikely. I'm sure your additional gonorrhea and chlamydia tests will remain negative.

That completes the two follow-up comments and replies included with each question and so ends this thread. I hope the discussion has been helpful. Best wishes and stay safe.