Real Clear Politics Estimated Change in House Races over last week
As a yardstick for comparison, in 1994 the Republicans picked up 54 seats in the House, eight in the Senate, and twelve governorships. Interestingly in the Senate the Republican wins were actually much easier than they are now because six of the eight Republican wins involved retirements. In this case, Republicans will have to beat many incumbents to pick up that many Democrat seats.
By contrast, NPR has Democrats looking very likely to keep control of the House. While RCP already has a majority of seats going to Republicans, NPR claims that Dems only have to pick up a few of the toss-up seats to keep their majority.