I am usually a pessimist anyway but Obama is focusing on the swing states like FLA and Ohio and MI. Even Rove has been having trouble painting an optimistic picture on those states.
National average polls are not that meaningful when they include solid states that have high populations.
The past few years Republicans have been worse (er better) than Dems at predicting victory just before disasters even though at this stage both sides are trying to spin their best.
The question then is, where are the REAL national polls? And Ras has had Romney up consistently (gee, seems like 1994 where only he was right) for two weeks; there are rumblings that the Dems are now afraid of losing the Senate so badly that a 60 vote majority might be in the making (I doubt it, but possible). The fact that Obama is focusing on OH and MI and FL says that he KNOWS he can't win with his 2008 combination and he is the one who has to run the "inside straight" to win, not Romney. Even Ed Rendell said that PA was up for grabs.
But feel free to wallow in your pessimism.