As Mharr will point out, you can go to: https://steamcommunity.com/app/892970/discussions/1/4594236462791998675/

and press CTRL F to find Valheim, then download the files. Rename them and stick them here: C:\Users\me\AppData\LocalLow\IronGate\Valheim\worlds

This is on the notion you're using Steam Cloud. If you do manage to retrieve your save, make sure to turn off Steam Cloud afterwards. Back-up your game world every now and then.