Thank you Gunther. I'm not very good with computers or with steam, so I'm still not sure how to fix this.

However I did go to your second link and found others that had the same issue.
It has to do with Steam cloud, creating problems when using 1 computer (only 1 windows account user) but 2 different steam accounts.

From what I can read the solution is as below. But I'm a bit scared to do this. Might I accidentely delete my character or restore the Character to the wrong date?

HERE IS THE SOLUTION THAT ANOTHER USER WITH SAME ISSUE POSTED:
"Looks like the solution was to both uncheck save to cloud for Valhiem for both profiles AND delete the current local cloud backups for both profiles in:
C:\Program Files\Steam\userdata\<SteamID>\<AppID>
By deleting the folders there and the remotecache.vdf file, it wont overwrite the files anymore.

<steamID> represents a string of numbers which represents each steam profile. You have to do this for each profile which plays Valhiem.
<AppID> represents the app id for the game, which for Valhiem is 892970."