implantation bleeding or period?

My boyfriend and I had unprotected sex everyday while I was ovulating. I was 3 days late for my period. Then I started bleeding and it was way lighter than my normal period. Usually my period is super heavy and lasts for 4-5 days. So then it started getting heavier the second day, then got really light and was brown spotting. It's now the third day and all day there was pretty much nothing but spotting on and off. Now I am having pinkish bleeding. This is very weird and never happens. I'm curious if this could be implantation bleeding? Has anyone else experienced this?