One day period!?

So my partner and I are ttc, we had sex around the time I thought I was ovulating, I took several tests, one was positive the rest were negative. I thought since so many were negative that I was out this cycle as I was 20 days late with so many negatives. Waited for AF to show, it arrived on CD 53, but it only lasted a day if not a few hours. Any thoughts on what could be going on??