What?

cyn

So I was comparing 2 <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period apps</a> eve and flow and flow said my period was gonna start yesterday <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">eve</a> was supposed to start last week still no period but I keep getting slight cramps nothing bad once in a while is this normal?