678 days/2 days per hour = 339 hours of play.
I'd have to assume your comfort was 25 dropped down to 20 but without knowing it's going to be a little inaccurate. (my original math was comfort level 22 dropped down to 20)
So, you lost 5 minutes every 20 minutes, 15 minutes an hour.
15min/hr lost x 339 hrs played = 5085 minutes of rested lost, divide by 60.
You've lost 84 hours and 45 minutes of rested time.

Edit: I may have messed that up somehow, doesn't seem right