Aww fer crap's sake!

Dam.n Firefox did something really weird. It stopped respondng and then when I closed and reopened it it asked my to choose my user profile. I clicked “default” (the only one there) and got the message “Cannot use default profile as it is currently in use.” or something similar. All my bookmarks are gone and now I can’t figure out how to change profiles. Has anyone else had this problem? If so how do I fix it?