Can't sign in with the right account through steam

Here is my problem:

Been playing on linux with the itch.io portable install using my current username (snugglywuggly). Linux version broke yet again last week, so I decided to switch to steam with emulation. That worked, but it singed in automatically with an old account of mine and its not letting me switch to snugglywuggly. Anyone know how to fix this?

Thx!