I know this is just anecdotal, but I have come across at least 30 aquaintances that say they voted for Obama but will not this time. I know of NO ONE who is going the other way.
These polls are screwy.
Remember the 96 election with Dole and Clinton? There was no one that could be found anywhere that said that they didnt’ vote for Clinton in 92 that had changed their minds and was voting for him in 96. Yet he won with 49% in comparison to the 43% he won with in 92.