I upgraded my iPad mini this morning to iOS 9.1. I have the first gen iPad mini. Since iOS 9 I have been experiencing app crashes and my iPad getting stuck a lot, but since upgrading to iOS 9.1 my problems have upgraded to my iPad just going black while I'm doing something on it. When I press the home screen button it comes back on for a second before going back again. As if it's constantly locking itself. Tried turning off and on again, didn't work.
What steps should I do to determine if the hardware just broke or if I can fix it with software?