Khalija, don't get your hopes up *too* much, but I just started Steam and an update queued for Pillars! It took a few minutes to validate, and now the entire 5.9 GB file is incoming. Weird. I had the game installed, so I'm not sure what's up. I did open a ticket with Steam a few days ago, so maybe they are getting around to fixing it.
Maybe try restarting your Steam client and see if it updates for you as well.