I'M SO CONFUSED!!

Jessica
My <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period tracker</a> app says that I'm 3 days late. Glow says I'm supposed to start on the 17th. <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> says I'm 2 days late.
I don't know which to trust. <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Period Tracker</a> is pretty spot on more than half the time. 
I'm just so confused. I've been feeling small cramps for the past 2-3 days.... 
I don't know what to do, or which app to trust. I know they're all just estimates, but I really like using the apps to help me keep track.
Ugh! 😡😠😤