When did I ovulate?

So, my cycle is pretty normal at 27-28 days. A week before I was supposed to ovulate I had a ton of ewcm. So I thought I ovulated early. Today, mid-cycle I am having mittelschmertz cramping (I think). Not temping or opk's. Had anyone experienced this? What do you think? Am I ovulating now, when I should be, or a week ago?