Hi good day..my last period was january 22 2017 and now im 15days late..i had sex with my bf last february 2,12,19,26..i tooked pregnancy test 5 times but its all negative..last sunday( february 26)4 hours after intercourse i tooked postinor 2 at once and now after 3 days i started to bleed..but its a light bleeding..could this be my period??is this because of postinor 2 ??..thanks very much appriciated for your answers