Help! Ovulation predictor off?

Lydia

Ugh, Im so sad. I swore I was pregnant. My period was late, but today I started my period. Took a pregnancy test to confirm and it was negative. Im confused because we TTC when I was in "high fertility" but after I put my period today, the week I was in high fertility changed? Idk what to do now? Was I not ovulating afterall? Whats the best way to know when to try? Appreciate any advice!