How many days past ovulation does implantation bleeding happen? I'm going on 7 days late for my period and have never been more than 2 days late for my period. This afternoon I had a little bit of brown blood (I know that means it's old blood) on my liner, but nothing else since then. Possibly the start of my period super late? Or could it be implantation? Waiting a few more days until I test. Just curious what you ladies think.