It's most likely caused from regular/constant saving, or it getting iterrupted during saving. You just said your last backup was on the 6th, which is a few days ago, so I'm not sure why you are saying you need to set it up from scratch again - unless you had nothing done in the last backup.
My recommendation is to backup your ved before & after any major changes, or better yet use the incremental save feature that VS provides instead of overwriting the same ved file constantly. There is a save option available when you have a ved open & open up the main menu, which says: "save as 'name of ved0001' or something along those lines, which will allow you to save a new version of the ved with an incrementally generated number instead of overwriting the current ved. Just do that every so often instead of risking corrupting your ved file due to incessant saving.
Also make sure you regularly backup your ved & resource files to google drive, dropbox, or some place similar, & to external usb hdd/sticks, etc.