Implantation bleeding??

Britni

So I’m about 16 dpo and I was supposed to start my period yesterday. I started cramping but only a little not like my usual period cramps, I can barley feel them it’s more in my lower back. I started bleeding today but it’s barley any is there any chance this could be implantation bleeding this late? Even if my ovulation day could be wrong? I also took a hcg test this morning and it was negative.