HELP COULD I Be PREGNANT?

Sheila
So on April 7th my period ended and my ex  and I had unprotected sex and I don't know if he ejaculated inside me. However yesterday I bled for a couple of hours had to wear a pad. Then this morning I woke up to use the bathroom and when I wipe its brown blood could this be implantation bleeding as this is to early to tell I know but this never happened to me before and this morning I still feel cramping. Could someone help me understand what this is please would really appreciate thanks.