Oh for sure. If we lose in November, it’s over! And no that is not hyperbole.
I've heard the same wailing in the past, and I remember what happened in the mid-terms during Obama's first term. He had strong majorities in both houses of Congress, but the Pubbies retook control of the House in 2010.
When, not if, the pendulum swings back, the Democrats will be sorry they ended the filibuster.