Yeah it sounds like a software glitch
Yeah itís sounding more and more like a bug. Here is what I recommend you doÖ
Backup your phone to a computerÖ
Check your Gmail account (make sure you can log into it on a computer)Ö
Do the factory data reset.
This should get your phone working correctly again. Just make sure you backup your information before the reset. Itís going to make your phone think itís brand new again.
Good luck and let me know if you have any questions.