If Barney Frank, Patty Murray, Barbara Boxer and Alan Grayson are in trouble, this is 1894 redux.
After the 1894 election, the Republicans controlled both Houses--244-105-7 in the House and 43-39-6 in the Senate. They went from being down almost 2-1 in the House to having a better than 2-1 advantage.
The reason for the turnaround: the Panic of 1893 (that is, economic depression).