Questioning my fertile days on my Glow app.

I've taken ovulation tests since April 10th, only had 3 positives.. Which is strange. The 11th & 12th and then today 21st so im assuming im ovulating sometime today and tomorrow, but my <a href="https://play.google.com/store/apps/details?id=com.glow.android">Glow app</a> isnt showing today as my "most fertile days". Does anyone know how to add it in or how it actually works?