Project opened up empty; no auto saves for it . What the heck?

So today I tried to open a Premiere Pro project that I’d spent many many hours on, only to find it was not among my “Recent” documents files. Everything I’d worked on in the last few weeks was missing. 

On navigating to the project file and opening it, I found that it was completely empty -- all my imported files and sequences were gone and my timeline was empty.  I checked my auto-save only to find that over days of work, there were apparently zero auto-saves made of the file.  

So it looks like I have to do a week of work over again. Does anyone have any idea how this happens?  

Do I have to keep multiple copies of every Save in order to prevent this from happening again?

This is maddening.