Try a reset. Close all apps then - Hold down the HOME, bottom button, and the SLEEP, top button, for about 10 seconds until the Apple icon appears, then release buttons. Allow it to reboot, it may take a few minutes, don't panic like I did, wait for it to reboot. Cures many weird problems on iOS devices. If that doesn't help, you must hook it up to the computer that it is synced to and do a restore.