heavy implantation bleeding

Is it possible to have a heavy implantation bleeding. Yesterday I was 12dpo, I'm usually a 32 CD so I should have gotten my period on this Saturday, but instead my "period" came 2 days early? I was wondering if it could be my period? Or if It could be implantation? When j was pregnant with my son I was 1 month and 4 days pregnant and didn't know because I believe I had a period, but then again back then I wasn't ttc so I didn't really pay attention to my body or anything. If y'all have any implantation stories it would be good to hear.