Originally posted by Flare |UKCS|:

No .old files in your worlds folder ?
You can recover lost worlds by renaming the .old by removing the .old extension (make sure you backup before messing with these)

edit: dunno if this works with cloud saves though

if you turn off cloud saves in Steam global.. then rename files at world_local this should work.. . Open and play game for a check ..then re-enable Steam Global cloud saves. Then most recent should be sent skyward ..GL