Sounds a lot like what I had Ellajoy. I don't know what day in my cycle I am since I haven't had a proper AF since coming off the pill, but from my temps and CM I'm quite certain that I did O on Monday/Tuesday. I was ill from Tuesday through to Friday night and it was so bad I was on the verge of throwing up more than once, with Wed being the worst day.

Feeling fine this week so far though