Early period? Implantation bleeding???

Al
I was really drunk one night and not completely sure if I had sex. I started spotting a day before ovulation which has never happened but I was told was normal. But now I just got my "period" five days before it was supposedly due. It seems lighter than usual but I've been using pads and tampons for the past 2 days. Could this be heavy implantation bleeding or my actual period?