I'm sure you don't need me to say this now, but I typically save a new copy of the file on a daily basis. ProjectName##_fileDescriptor.ma (e.g. PanzerIV07_modelling). Others have more stringent and file heavy systems like incremental saves every five minutes creating new files, keep the last 20 or something.
As thats an MB file format thats gonna suck trying to get an ounce of info back from it, had that been an MA file chances are that would have recovered because they store more info.
I had this happen years back on both accounts.
for the record, I learned from a colleague of mine who came from Weta that an MA file is a good way of saving scene files that have issues, they are bigger files but they tend to clear out the crap, kind of like an obj but dont strip out everything important you'll need.