Help ! Project Minimal Default Map Overwritten by new Asset

I can’t believe this, I purchased an Asset pack of some floral arrangements on Marketplace. I clicked ADD TO PROJECT button. When I returned to my project my Minimal Default map for the project had been overwritten. Months of work gone. I see Log files of pre asset addition but the only minimal default files I can find are a starter map and the overwritten file. Are there no copies of previous Auto Saves stored someplace ? Is there any way to recover my original map ?