Updated to OS X Yosemite, everything has deleted
Since you can see your "stuff" it is still there but under another user.

Somehow you made a mistake and created a brand new User account with nothing in it so now you have 2 users on your computer each with they separate folders and files.

What you need to do is to log out of that user account (go to Apple icon top left and select log out).

Now you can log in in to your other user account.