Ovulating?

Megan • Mama to our little rainbow-Finley James
Glow says that I am in my fertile window but I have been using OPKs and haven't gotten a positive one yet.  My peak day is supposed to be tomorrow.  My last AF was the first one since my natural MC in January, so I'm worried my cycle may be off.  This is my first time trying to use OPKs to track ovulation.  Is it possible to still ovulate even though I don't get positive OPKs?