Hi Brocke,
When you log out your game should be automatically saved for you. Upon returning to the game client you'll be presented with an option to resume or forfeit. From there you just need to choose resume to pick up where you left off.
If you're not seeing the resume/forfeit option when you first load the game client then unfortunately that round has been lost. You can only have one save state at a time and you can't do anything else until you finish or forfeit that game.