Turn your data and WiFi off, ya only need your phone as a phone when when your sleeping
That there is what I do, and Bluetooth too.
Also if it's an android phone pull up the recent apps and close them all, just before you put the head down to go sleep.
Ohhh and I've never experienced that problem. Hopefully it's just a bug and it's sorted now.
If not, uninstall the app and reinstall it