My Moto G is fully charged, I was checking my calendar for the day and the next thing you know the screen goes black and it won’t turn back on. . . please help!
Take a look at Troubleshooting Guide by Motorola
Is your calendar app native or a 3rd party app? Could be a app problem.
In the mean time try holding the power button down for 10 seconds or so. That should force the phone to reboot so you can have a working screen again if it is just an app problem.
If the phone has shut down and won’t restart then you may be in a pickle. Is it less than a year old?