So today is the 18 and I have some  light bleeding...I know that I've been ovulating from the 11 till today. I did have unprotected sex with my SO on Sunday the 13 and again on that Wednesday and Thursday. Do u guys think this is implantation bleeding or could it be from a biopsy I had last month. The first time I had sex after that I did bleed really bad but I haven't experienced any bleeding since then.