The usual fixes when something isn't working the way it should (in case you didn't try these already):
Restart your iPad:
Turn it off, wait for a few minutes and turn it on again.
Reset:
Press and hold Home and Power button simultaneously until the Apple logo appears.
Force close apps:
iOS 6: double tap Home button or four/five finger swipe upwards to reveal multitask bar, then tap and hold an app icon there, until it starts to wiggle. Delete all the apps there.
iOS 7: same double tap Home button or 4/5 finger swipe to reveal it, now tap one of the thumbnails above the app icons and drag it upwards towards the top of the screen.