That rate of discharge has nothing to do with iOS6.

Us a little common sense - if you slept until 8AM, that would be 10 hours of standby. Apple talks about 200 hours or more of standby.

The most likely cause is a corrupted file. Open iTunes, connect with a wire. Before a Restore (no need to backup, cause you are not going to want to pull a corrupted file from your backup), when given the option to pick a backup, say no and choose factory settings.

This will take some serious amounts of time and you will have to manually move all contacts, emails, etc. over to your iPhone. Additionally you will have to download a fresh all apps, reset manually all settings, etc.

Gordon
Atlanta