windows live mail – all emails and folders disappeared

I've been using windows live mail 2012 for years with no problems. I had several folders created to store emails i wanted to keep on various topics This morning, all of a sudden, while reading my inbox, emails that were shown on the list appeared blank in the reading panel. I decided to reboot to see if it would fix the problem Instead, all my emails, folders, ... seem to have disappeared. It is as if i am starting with a blank email store folder... and it started resynching with my yahoo account .... but all my saved folders are gone any idea what might have happened? how do i recov