Countdown 12 Days

I was told today by a kid who raced on one of the best college cycling programs in the US, "Marathons are the best things in the world if you can actually run them. You feel every emotion that you could possibly feel in the course of 26 miles." I agreed and for about 2 hours felt the motivation that was necessary to run the 20 miles that I should have run last night. Today after ramming my gut full of MSGs at good ole House of Taipai, I felt the need to make up the sleep I was shafted all this week (there was definately a 2 hr sleep night this past week). After a nap, I realize that I have to push this run to tomorrow after work. This run is looking less like training and more like a nagging cough. How does anyone run an ultra?