As much as I hate to say it, you're probably gonna need to do a factory reset.
I could go on and on about awful default update installation methods are on Android phones, especially OTA updates, but I've already done that too many times. For what it's worth, it's not the update that is lousy, the update itself is great...it's the method of deployment that usually screws up people's phones. Most rooted folks who install ROMs are quite familiar with the recipe for success when it comes to installing new software, but basically when updates are applied, existing user data on the phone should be wiped first. It would be nice if Android provided a better way for un-rooted users to backup ALL user data to facilitate this...but as far as I know there isn't.
Regardless, your issue will most likely be fixed by doing a factory reset on the phone.