Characters randomly deleted?

Hello.

So as I was playing WoW Cataclysm less than an hour ago, the game crashed on me. At first when I tried logging in it just told me that I was "Unable to login at this time, please try again later". Upon succesful login, I was greeted with a new character creation screen, and confirmed with my friend that all my characters had been deleted since he couldn't see them on his friends list. Any reason why that is?

This may of course have been a case of being hacked, but I'm just checking in case something has happened without my knowledge.

Thanks for your time,

/MTG0504