Please help a girl out!

St

Does anyone else bleed at ovulation?

I've been taking fertility smart, which has vitex in it, because the reviews were amazing and I don't often ovulate. I've just taken an opk which was the darkest I've ever had (just shy of positive) but today I'm bleeding, more than spotting, almost like a period. (TMI, it had some tiny clots in it which is what's making me think it's not normal ovulation spotting). I'm only on CD18!! Anyone else?