You could try it again, and you could also try closing all apps via the taskbar and see if that makes any difference : from the home screen (i.e. not with any app 'open' on-screen) double-click the home button to bring up the taskbar, then press and hold any of the apps on the taskbar for a couple of seconds or so until they start shaking, then press the '-' in the top left of each app to close them, and touch any part of the screen above the taskbar so as to stop the shaking and close the taskbar.
