Is there still a possibility?

I was suppose to start 3 days ago. I thought for sure I was pregnant because I've had no symptoms of my period coming on. Today, while at the park with my husband and son, I had some cramping. We came home and I went to the bathroom and discharge was light pink. I thought okay.. it came. I just ovulated late, but it's here. HOWEVER, I still have no breast pain, the cramps stopped, and it's only light light spotting when I use the bathroom. Nothing on my pad. Normally my first day is the heaviest, my cramps are bad enough I stay in bed all day, and my back hurts so bad my husband has to put all his weight in it to relieve pressure. Is their any way I could have maybe have ovulated a week late and having implantation bleeding now? HELP!!