I just upgraded to 13.10 this weekend (I know 14.04 is out, I'm not doing that yet) and have lost my login. There used to be two user accounts I could choose to log in from on the startup page, mine and the dummy one created by a coworker when he was helping me with something. After the upgrade, the only user account I could log in to belongs to my coworker. My account data is still there (I can access it when I log in as him and cd to /home/username) but I don't know how to log in as my old user account. It also doesn't show up in the user accounts Settings view. How do I add it back?
Note: I tried using the answer to this question: Why are my user accounts missing from login screen after upgrade to 14.04 from 12.04 ? and got the response "user 'username' already exists"