By his count, Sam hadn't slept in four days, but then again, he wasn't really sure. Four days ago had been a lazy Sunday, and he had gotten up for about 20 minutes early in the morning to eat a bowl of Frosted Flakes and then had gone back to sleep for like five more hours, which was almost a quarter of a day. Whatever the case, he hadn't slept since Sunday, which was four days ago. Maybe that was a better way to put it.
By his count, Sam hadn't slept since Sunday, but then again, who the hell counts things like that? There has to be a number in there somewhere when you say something like "By his count." You couldn't say, "By his count, Sam's last car was green," could you? No. You could say, "By his count, Sam had driven the green car roughly forty thousand miles before it broke down," which would be a better sentence to boot on account of the extra exposition it allowed.
Sam was exhausted and confused. The plot seemed to be moving nowhere, and all because of semantics.