UPDATE
Got all of my work back. Thanks to this forum. Though I have a Mac, I used my husband’s computer to follow these steps: https://forum.audacityteam.org/t/corrupt-or-otherwise-broken-audacity-project-recovery/64162/1 and had my stuff back within minutes! HALLELUJAH
I am still feeling a bit strung out from the stress of that so would still appreciate advice on why this happened. Through my internet searching I see OneDrive might be to blame…?