When I took Clomid (3-7) I O'd around day 15 or 16, but everyone is different. Do you use OPK's? Some women with PCOS can't use them b/c they get false positives, but they work fine for me. I also chart and that's how I really know that I've ovulated. I use
www.fertilityfriend.com It's really easy, just type in your temps and it does everything else for you.
Good Luck!