HIV Post exposure medication

I’m 27 years old, Man. I had a sexual intercourse with one women( my exgirlfriend, she is a foreigner, UK born indian), known her for 4 years but now only i get to know that she is into bareback intercouse with multiple partners. She last checked for HIV was on last year June, 2018. Initially she said she had not intercourse with anyone after June but today she said she had intercourse with few white guys who unknown status of HIV as well before this. During the intercourse i do wear condom but unfortunately the condom breaks as i was abit high due to alcohol consumption during thats time and i just noticed a very little streaks of bleeding in my penis. This made me more worried and one of my medic friend told me that if i exposed to person who unknown status of hiv, i must take post exposure prophylaxis immediately or atleast within 72 hours. Intercourse happened on Monday(15/4/2019 around 3.30am to 7am). I didnt expect this would happen but this really scared me. I have checked the HIV rapid test yesterday was negative. But my friend said the incubation period for HIV would be more or less 6 months. So the results could be false positive or negative as well. Can you do guide me where can I get the prophylaxis?