clomid always made me ovulate around cycle day 15-16 so you still have time.
Clomid can definitely change the timing of your cycles. While I was on it, it made me O later than normal and I usually got my + ovulation test on cd 15 or cd 16. I was freaked out too my first cycle on it because I thought it totally screwed me up, but everything ended up being just fine. Hang in there, I'm sure you'll O soon. Good luck to you!
Did you only do an ovulation test just now? Usually you get your LH surge anywhere from 12 hrs to 2 days before you O. Did you test before today?