I have the exact same problem, and then suddenly you notice that it is 5 hours later. And when you have completed the map you say, ok let's just start a new game and do the first turns. And then you are back from the start: Ok, one more turn and i'll go to sleep...ok one more city and i'll go to sleep...alright one more level for my hero and i'll...etc

Luckily there is a realtime clock now, so you know what time it is. I only dont look at it, i am to busy with the game itself. Even while the PC is doing its turns. Then i am thinking of what i am going to do the next turn.