Hi,

You probably have another user account on your device and you have to switch users.
From the top of any Home screen, the lock screen, or an app screen, swipe down with 2 fingers. This opens your Quick Settings.
Tap Switch User.
You find more info here:
https://support.google.com/nexus/answer/2865483?hl=en

Let us know if it worked.
In case it didn't, please send us more info directly about your operating system and device model.
Thank you!