Why do I say that? For one thing, President Obama's approval ratings are now rebounding. For another, the president's approval ratings (43.3% average) are still nearly four times as high as those of Congress. A recent Gallup Poll, taken between February 6th and 9th of 1,023 nationwide adults (with a margin of error of 4 points), shows the job approval rating of Congress is still amazingly low -- only 12%. It's been a decade since Congress had an approval rating near that of the president (in the low to mid-forties).
And this disapproval of Congress cuts across party lines -- with only 23% of Republicans, 7% of Democrats, and 9% of Independents saying they approve of the job Congress is doing. I expect that Republicans will vote for Republicans and Democrats will vote for Democrats in November, but that low approval by Independents should worry Republicans, who hold the majority in the House -- especially those 50 or so Republicans in competitive districts. There seems to definitely be an anti-incumbent feeling in the electorate, and it would only take the Democrats winning 17 of the competitive Republican seats to seize control of the House.
President Obama's approval ratings may be lower than they were a couple of years ago, but the president is not running in this coming election -- Congress is, and their approval ratings are in the dumps (with GOP congressional ratings being significantly lower than those of congressional Democrats). Congress, especially the Republicans, have earned these dismal ratings all on their own -- and I doubt the ratings of President Obama will affect their electoral fortunes one way or the other.