Re: WOW- I lost my pet bar!
As Ninjaman stated, get a good action bar addon, and you will not have this issue anymore. Search for Bongos2 or Bartender3. They're both excellent addons.
Bongos2 - The more complete addon, it has more features than Bartender, and the keybindings mode is friggin awesome. However, a lot of updates reset your profiles, and that's one thing I hate about Bongos.
Bartender3 - Easier to setup for a novice, more frequent updates, but the rep bar is buggy. Disable the rep/XP bars and get a seperate addon.
I prefer Bartender now after being a longtime Bongos user. I just have to use XPBarNone to replace the rep/XP bar, and I prefer Squeenix for the minimap anyway, so I don't need the Bongos version. While I do miss the Bongos keybindings, I don't miss having to reconfigure my UI after every update.