I was playing world of warcraft, but couldnt because of update, after update my characters were gone? help plz?

well i asked a game master and they said i needed my name and realm. what does realm mean. and i dont know my characters name!! i know im stupid D= but is there any way to get my character back. maybe the update is still on going will they appear later? or wil lthey be gone forever o plz help :(