Did you manage to get preg? Cux I'm facing the same issue now. I test for ovulation since the 8th day of the cycle till the 16th day of the cycle. On the 15th, was my peak and I had intercourse. I have missed my period for a few days. When I test for preg, it was negative too.
ovulation kits can show positive for many days.. the counting might be a bit off if you use fixed 14 days. luteal phase can vary!