14dpiui BFN

Judi
14dpiui and BFN 😟 I used OPK this time. Can OPK be wrong? Does this mean I did <a href="https://glowing.com/glow-fertility-program">IUI</a> on wrong day? Anyone got bfp after getting BFN on 14dpiui ? AF has not shown yet and no sign of it.
With ultrasound I had <a href="https://glowing.com/glow-fertility-program">IUI</a> on day 17 and with OPK on day 15. Should I wait two more days for AF?