Period is 2 days late

According to the <a href="https://play.google.com/store/apps/details?id=com.glow.android">glow app</a> my period is 2 days late. Usually it comes 1 or 2 days before it ever predicts it anyway. Took a pregnancy test from the dollar store and didn't see a positive. We have been ttc for 2 years and they say there aren't issues. Could it just not being showing up yet?