...Not likely. I know the media outlets have been buzzing about how the country is dissatisfied with the Democratic White House and Congress at the moment, and also how the Tea Party is picking up a lot of popularity, but it would take a lot for the Democrats to lose the House, let alone the entire Congress. The Republicans are currently up against a large number of incumbents in Congress, and a little fact that the media doesn't often mention is that incumbents win.
For anyone who hasn't taken much PoliSci, an incumbent is a politician who is running for reelection. At least in American politics, incumbents tend to have a sizable advantage over challengers, especially in Congressional elections. For one thing, members of Congress don't have to pay postage. This may not seem like a big deal, but think about the millions of pamphlets and other campaign items that Congressmen send out to their districts, and the cost of stamps start to add up.
I would go into more examples, but I know how boring it would be, so I'll just sum it up this way: It doesn't matter what party you are, if you're a member of Congress, you want to continue being a member of Congress. Regardless your party affiliation you want to be able to get reelected. And it's a handy fact that members of Congress happen to be able to pass the laws regarding election regulations and such.
Now I'm not saying that the Democrats won't suffer losses. They won a lot of seats a few years back that originally belonged to Republicans, and odds are they'll lose a few, if not all of those. But honestly, to gain a majority in Congress, the Republicans would have to win more seats than they did in the 1994 election, to which the current election has been much compared. So again, could the Republicans take Congress back? Sure. Will they? Not likely.