Why can't I exit Ultra Power Saving Mode??

A

AC Question

Hello people!
I have a Samsung Galaxy Ace 4, and I pressed Ultra Power Saving Mode, and my screen turned black and white, but I can't see the Ultra Power Saving Mode screen. I can see my regular home menu, but in black and white. If I pull down the menu from the top, there is no button to push either... I tried going in Settings, then clicking on Ultra Power Saving Mode. The switch was turned on. I turned it off, and nothing happened. I closed settings, went back again, and It was on... I must have tried this about 20 times....
Can anyone help me please?
Thank you.. :)