Your game progress is automatically saved to the cloud, that's why it shouldn't disappear even if the game isn't connected to your Facebook profile in the game settings.
However, in very rare cases, game progress gets wiped out. To avoid this, you need to connect the game to your Facebook profile. This will help us find your account much more quickly!
If you can't connect the game to Facebook, just copy your game ID and save it somewhere before you reinstall the game. And if your progress does get lost, send us your game ID number, and we'll bring your game back.