In the absence of any road map, House leaders shuttered the chamber Thursday for a six-day weekend, putting lawmakers in standby mode and scheduling the next votes for Wednesday evening, two days before the shutdown deadline. (Aides cautioned that the schedule could change.)

“No one has any idea what the play call is — we don’t know what’s going on,” said Representative Ryan A. Costello, Republican of Pennsylvania, who, because he is retiring, has already surrendered his office suite for a cramped cubicle.

“You don’t have an office,” he added. “You’re in wind-down mode, saying goodbye to people and wrapping up, and just putting your voting card in the machine and pressing red or green. It’s going through the motions.”

And he’s one of the lawmakers who have actually been showing up. In recent weeks, anywhere from a handful to more than two dozen Republicans have failed to cast votes on individual bills, leaving leaders uncertain of their numbers. Some lawmakers cited personal reasons; Representative Lynn Jenkins of Kansas, following guidance given months ago that Congress would adjourn by Dec. 13, may miss votes to get married, while Representative Walter B. Jones of North Carolina, who was re-elected, is taking a leave because of illness.

Mr. Trump himself is scheduled to leave on Friday for a 16-day vacation at his Florida estate.

But even those who have no pressing commitments have grown weary of trekking to the Capitol as Congress grinds to a close. One senior Republican aide, speaking on the condition of anonymity, said some lawmakers no longer even wanted to see one another’s faces.

“There’s a temper to the House, and it starts to get dark by the end of the year,” said Michael Steel, a Republican strategist who was a top aide to the former Speaker John A. Boehner of Ohio. “Members start out very, very eager to legislate, to make progress, to refresh from the holidays, and by the end of the year, there’s a great deal of friction and tension and just built-up frustration.”

That dynamic is all the more potent for Republican leaders who have spent the last two years trying, with mixed success, to govern while skirting the unfiltered remarks and tweets of a president who cares little about the finer points of legislating, and whose agenda often diverges from their own. Now they find themselves trying to cope with the no-win situation Mr. Trump has created as he insists on building a wall supported by a minority of Americans.