Positive ovulation, no period, not pregnant

Špela

At 16th of July I had positive ovulation clearblue test and have BD every other day at that fertility week. Today I'm 18 dpo, period is 5 days late, pregnancy tests are negative. What do you think is going on? If I didn't do ovulation tests I would think that I just didn't ovulate or I ovulate later, but I had confirmed ovulation test.