Why is my phone stuck in ultra power saver mode?

[Android Central Question]

My Galaxy Grand Prime got stuck in Power saver mode when I found out that U.P.S.M. disappeared from the notification bar. Nothing works I. The phone again asides 3 applications(Contacts, messages and Calculator) and even when I go to settings, the Ultra Power Saver Mode can't be turned off from there.. Please help out, thanks a lot.