Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice.
As you took post exposure prophylaxis, and test results were negative even at 12 weeks; it's very unlikely to be
HIV. So, you should not worry a lot now. But be very careful regarding your sexual practice in future.
These can be effects of drugs but after stopping drugs for so many days, it must have settled by now.
Your third question is important. I think, we should think of other sexually transmitted diseases rather than HIV only, especially
syphilis,
gonorrhea, or chlamydia, and
herpes.
So, I would suggest you to see a doctor and get screened for these diseases as well. Antiretroviral drugs doesn't affect your HIV tests. So, negative means negative.
Hope I have answered your query. Let me know if I can assist you further.
Regards,
Dr. Mahboob Ur Rahman