Implantation bleeding or period?

For the past week or so I have been feeling nauseous and sick. Regular early pregnancy symptoms. I am 10 dpo today. I've been cramping for the past 2-3 days. However this morning I woke up and I was bleeding. It's dark red and a little brown. And it's heavy. Like a period. But some are saying it could be implantarion bleeding. However if it's my period then it's 4 days early. My periods are never ever early, sometimes late but not early.