Is it likely that I could be pregnant?

I stopped taking the pill 3/14 (midway through the pack). I thought I might have ovulated 3/22. Now, 8 days post ovulation, I have backache and am more tired than usual. My husband and I did have 3/21, 3/22 and 3/23. It's still to early to test :-(...but based on your personal experiences, do you think there a good chance I am pregnant?