Sounds like corruption from a software update. To fix this issue, follow the steps below:
Disclaimer: Following the steps below will wipe the data off your phone. I am not responsible for any data lost from the steps below.
1. Hold the power button and volume down button.
2. Do this until a white screen appears, release buttons immediately.
3. Use volume keys to navigate the menu, volume up to go up, volume down to go down
4. Navigate to the "Factory Reset" make sure it's highlighted which means it is currently selected. Press power button to select that option to factory reset and the phone will do the rest for you.
5. It will take a few minutes to boot after the factory reset.