UI Reverted?

[Smurflogik]

Just logged in after being logged out for no more than 30 minutes, and all of my UIs on all of my toons have reverted to exactly the way they were more than a year ago. There are gaps where my 2nd and 3rd hotbars used to be. My hotbuttons and keybinds are different. Even my /target and /assist macros have names in them of players that haven't played in nearly 2 years. It also seems that my logs are no longer updating or writing new data, even though they appear to be on.

I didn't change anything at all while I was logged out.

Any idea what could've caused this? Anyone ever hear of something like this before?