You get the message because you turned off the GPS. GPS only uses the battery when you use it.
You could have app that is syncing far too often. Or maybe at work your device goes back and forth between 3G and 4G , that will kill a battery quickly My S4 lasts the day no problem.
You could try to place the device in safe mode for a day and see if the battery life improves. if so, then it is an app issue.
1. Switch off your phone completely.
2. Power it on again.
3. Now continuously keep pressing the left key.
4. Keep pressing the key until the boot is complete and the home screen appears.