windows live mail deleted all messages and sub-folders

I am using Windows Live Mail 2012 with Windows 8.  Last night, everything was fine.  When I checked my email this morning, ALL of my messages were gone, all folders were empty, and all of the storage folders I had created are also gone.  Everything was correct when I checked email before bed, and Windows Live Mail was not left open over night.  When I opened it this morning, it did download all of my emails that had not been deleted from the server of my email provider, but that was not anywhere near what has disappeared, and of course doesn't include missing folders.  I am at a complete loss.  Can someone please help?!