Why are Democrats privately fearing losing the House?

Given the unforeseen downturn in the economy and a slower growth, the reinforcement by Bernanke that the Fed will do all they can to ist in an improvement shows that the administration's policies have been ineffective and, eight months after Obama's SOTU address when he promised to make jobs a priority the reality has been quite the opposite. That many voters are concerned about his administration's position on illegals and, that his focus and energy were expended on his health care insurance reform bill which caused jubilation within his party, that one triumph became his Pyrrhic victory. He won the top item on his agenda but at a bitter cost. Voters continue to suffer and they will remember and, the Democrat leadership know it.