I had unprotected sex on the day my period ended (16 Jan) and then i took plan b pills late since I do not know about it before, like on the fifth day after me and my boyfriend had sex and we are on withdrawal method, Now (26 Jan) I'm bleeding, like heavy bleeding during period, not spotting, is it implantation or am I just having period? And, can I still be pregnant after that? I took a pregnancy test since I'm bleeding and it came out negative.