U. Saving mode wont turn off

[AC Question]

I put my phone on u.saving mode to help charge quicker but when I unlocked phone an hour later it has regular home screen display but in black and white, app icons are all gone except for contacts and messages. Pull down screen doesn't fully come down and settings only has options for brightness,volume, mobile data and that's about it... Unable to access any other settings including battery option to turn on/off power save and u. Saving mode.