How Early Can HIV Infection Be Detected After A Possible Exposure?

had a high risk exposure, messing with a male friend unknowing of how many women he had slept wit before me, he told that he had been tested and eveything was okay (not sure how truthful he was) but nonetheless we continued to have sex with a condom both times but he was in me for less than a minute without one on he date of december 27, 2016 got tested for hiv on january 31, 2017 (which is about 35 days) with an insti rapid hiv 1/2 test at my local clinic and tested negative, what are the chances that my negative result will become positive at day 42?