If you were a fresh spawn:
You have probably died when log out (your character is ingame for another 30 seconds after you exit a server) or you died when you logged in (your character stands there for at least 3 seconds when you are still stuck on "Please wait" before you see your character.

If you were naked:
Maybe someone saw you log out and knocked you out and then looted you.

Please refer to the primary character save loss thread at #78

Thanks