Welcome to the Forum and thanks for your confidence in our service.  I'll be glad to comment.  I am going to presume that there was no penile-vaginal penetrative sex during this encounter, both because your partner says there was not (why would he not tell the truth after the fact) and because intoxicated or not, you would have remembered.  Moving on to oral sex, this was a virtually no risk event as well.  Performing oral sex on a male partner is very, very low risk- the CDC suggests that the risk for acquisition of HIV from performing oral sex on an HIV-infected partner (and it is very unlikely that a heterosexual 21 YO male has HIV) is less than 1 infection for every 10,000 sex acts.  As for your receipt of oral sex from him, again the risk is very low- probably even lower than the risk of performing  oral sex on a male partner.  Neither Dr. Handsfield nor I have ever seen a woman who acquired HIV from receipt of oral sex.

As far as other STIs are concerned, again, the risk for infection was very low even before you took the azithromycin because most people do not have STIs and even when they do, most single exposures do not result in infection.  The azithromycin you took would lower any risk even further, killing much gonorrhea and most chlamydia. 

All in all, this was a very low risk event, both for HIV and for other STIs and I would not worry about having been infected.  I hope that this perspective is helpful.  If there are further questions or any of this is unclear, please use your up to two follow-up questions for clarification.  EWH

The decision to test is a personal one.  given the circumstances you describe, I would not test but if you choose to test, that is fine although the timing of testing is important for accurate results..  Tests for gonorrhea and chlamydia can be done at any time more than three days after the encounter.  Trichomonas can be tested for at that time as well.  Tests for HIV and syphilis will not be reliable until at least 4 weeks and preferably 6 weeks after the encounter.  If there are visible lesions, they can be tested for herpes but we specifically recommend AGAINST blood tests for herpes as these tests are often misleading due to both false positive and false negative test results. 

When persons get oral herpes the lesions are typically on the lips, no the throat. 

The sore throat of HIV is typically accompanied by high fever (over 101, muscle and joint aches and occurs between 7 and 21 (28 at the outside) days after acquisition of infection.

Your experience with google is all too common.  So much of what is there is overstated, taken out of context, out of date or just plain wrong.  I urge you not to use Google to guide your manage care.

Hope this helps.  Again, please use your final follow-up question if I have missed something.  Please don't worry.  EWH

Please re-read my comment above regarding Google.  This is not HIV!!!!  Fungal infections in HIV occur in persons who have been infected for years. 

Nor is this likely to be an STI. The great majority of oral STIs are asymptomatic and do not cause the sorts of lesions you describe which are most often causes by non-STI viral STIs of the sort most people get from time to time. 

The azithromycin you took could have pre-disposed you to getting a fungal infection but what is really much more likely is that this is a coincidental community acquired, non-STI viral sore throat.  Please don't overthink this. 

I think you know, we provide up to three replies to each question.  This is my 3rd reply, thus this thread will be closed shortly without further replies.  EWH

Your thread was not closed after my last reply so I will go on and reply, after which the thread will be closed.  I understand that you continue to be quite concerned about STI but once again,  want to reassure you that this is most unlikely.   The likelihood that this is an STI was negligible even before you took the azithromycin and the azithromycin would reduce your risk still more.  I suspect you have a lingering, non-STI, community acquired viral sore throat which you may have gotten from almost any acquaintance or through your activities of daily living. IF you had it, 1500 mg of azithromycin would have cure most (about 3/4) gonorrhea infections.  E. coli is not a cause of sore throat. 

Given your continuing concern, you may wish to see your own doctor.  If you do and she/he decides to test, unless a specific test is performed using a throat swab for gonorrhea, the test will not detect gonorrhea, focusing on strep.  I obviously do not know of your relationship with your own doctor or the availability of testing but my sense is that being seen might be comforting. 

Again, I hope that my reassurance will help.  This thread will now be closed.  EWH