vitex, fertility herbal?

I started taking vitex 3 days ago, had weird ball like cramping on the left side the second day. And this is the third and I am having small little cramping. I've never had this kind of cramping. Could vitex made me ovulate immediately? I am on cycle day 31. No idea when af is due considering its ranged between 29-39 in the last half year. I don't think I ovulate. Any one else have experiences like this? Thank you