Me and my bf were fooling around and he rubbed his penis on my vagina , this was 5 months ago.I ve been having periods but they always start of as stringy black blood but turn into full periods, they have been coming every 2 weeks, I also have taken 4 pregnancy tests all a different times since the incident, last one was 19 weeks after, all have been negative . I have convinced myself I m pregnant, I had irregular periods before this also but not with the dark blood. Would the preg test still read negative this far along?