Thanks for the quick reply.
I altered two of my javascript files and my index.html file. I was running the simulator and all was working well so I went back to add some more javascript and then the file wouldn't save. Appbuilder was not responding to anything, so I decided to wait it out. Once the status page showed the appbuilder back up I logged back in but all my recent work was gone.
You must have rolled back to an earlier version that did not include my recent changes. Is there any chance of restoring them to the later working state?