I just took some blood test as suggested by my doctor. My issue was initially frequent urination so he asked me to take blood test, there are many (diabetes, prostate, kidney, etc) but I am not sure if one of them can detect HIV.
My exposure was in February, intercourse with a sex worker, a month after the exposure I had a very bad sore throat and very high fever that I had not been experiencing for a long time. So I guess it's been 9 months.