I actually from ESPN Radio that the Eagles center (Fraley) said in an interview that McNabb was so exhausted in the 4th quarter that he was nearly vomiting in the huddle. He said that McNabb was so sick trying to hold back his vomit that he could not communicate to the team which play to run, which as one of the reasons why Philly was taking so long down the stretch. Appareantly Freddie Mitchell ended up calling one of the plays in the absence of McNabb's voice.
Again, it would be nice of someone from Philadelphia could confirm this. I don't see how the humidity or temperature change could have made McNabb THAT sick, but who knows. Andy Reid has taken much of the blame for the offensive blunders, and I am not sure if this is an excuse for McNabb's uncharacteristic style of play Sunday. Either way, the Patriots outplayed them.