lightroom oddness

[Combat squirrel]

Hi all, iv been editing some wedding photos for a couple of weeks now, and I clicked on one photos flag in the top left corner while browsing through my flagged sets and it lost all the flags, gone, and cannot undo , its retained the edits and stuff iv done now iv got to go back through all 1200+ photos and reflag them any idea what happened here ?

 

[Combat squirrel]

yeah that would make sense actually, but I couldnt undo it after

 

[Combat squirrel]

One more question, if I was to format my pc and start again (mac), how would I save all of lightrooms settings + any work im currently doing (or does it save it on the 'raw file') ?