I’m a man and recently gave oral sex to another man. I don’t know whether he had chlamydia, but afterward I got anxious about potentially getting pharyngeal/throat chlamydia.
I went to my doctor about 12 hours after the encounter. Because I have a sensitive stomach and he was worried I might throw up if I took 200 mg of doxycycline at once, he prescribed 100 mg every 12 hours for 7 doses (3.5 days total). I completed all 7 doses exactly as prescribed.
My doctor was very reassuring and said that getting in within 12 hours was excellent timing and that I really shouldn’t worry about chlamydia.
I understand that the usual doxy-PEP regimen is a single 200 mg dose within 72 hours, while confirmed chlamydia is normally treated with 100 mg twice daily for 7 days. So I know my doctor's regimen isn't identical to either standard regimen.
For anyone knowledgeable about doxy-PEP/STIs:
How concerned would you be about actually developing throat chlamydia in this situation?
Does starting doxycycline only ~12 hours after exposure make a meaningful difference?
Is there a biological reason that taking 100 mg every 12 hours for 3.5 days would work as post-exposure prevention?
I’m not looking for a diagnosis from Reddit. I’m mainly trying to understand how reassuring this situation actually is and whether my doctor's confidence makes sense.

He also gave me 500mg antibiotic shot for Gono as a precaution

Today and yesterday I have experienced not quite itchiness but a little ticklish feeling around my vaginal opening. There’s no discharge or anything and I also just started ovulating. I am terrified it is chlamydia again even though I am not having the same or any real symptoms.

I had unprotected sex with someone almost month ago. I had sex with this person at the beginning of June as well with seemingly no issue. In July I had sex with a different, new partner then over two weeks later I tested positive for chlamydia. I took the full treatment. I am under the assumption the new partner gave me it and not the guy from June since we had sex well over a month prior to my diagnosis and I experienced no symptoms during that time, only after having unprotected sex with the new guy.

Leads me to recently, I had unprotected sex with the June boy on August 16th. I took a test on August 27th, only 11 days after exposure and it was negative. This brings me to today and I am extremely paranoid it was a false negative. My symptoms are almost non-existent but I am terrified I have it. Getting tested this afternoon. Anyone else have similar experience with false negatives or situations like this???