This might be a rare connection issue. Try starting a couple of buildings, logging out and logging back in to see if your progress is saved at all.
Make sure you check your Windows Firewall so that DoF.exe and/or Dawn.exe are allowed. Also try restarting your wireless modem/router.
In the future I would recommend logging out every 30 minutes or so, and logging back in - to make sure you don`t loose too much progress, as this bug might still effect you from time to time.