Well on the steam/windows version there has been several issues with authentication that led many people to have an “alter ego” at 0 level, like a new character. I’m not saying it’s your case. Try and check if by mistake you changed name to your clan.
There was another person that was complaining that in single player he built as a player, then created a clan, then changed the clan name and all his single player stuff was screwed up, like he couldn’t open chests but he could open doors or something like that.
But the fact that “single player games” have multiplayer decay timer enabled by default and no save slots for multiple games should get us to think in what state the game is. Early access that is.