Allardyce's side are in the top half on the back of four straight wins in February, but their momentum was interrupted by defeat at Everton and then a weekend off as scheduled opponents Hull City played an FA Cup quarter-final.
That game has been rearranged for March 26, but there is no date yet for the London derby with Arsenal - originally scheduled for April 12 but now postponed because of their opponents ongoing FA Cup commitments.
West Ham are six points clear of 18th-placed Cardiff, and Allardyce said: "There's not a huge amount of difference between 10th and the bottom three so that can change very, very quickly.
"Falling games behind is not what you want to do. To make those games up and points up, where others have played games if they've picked the points up is a difficult task.
"I think we're going to fall another game behind in a few weeks' time when we
were scheduled to play Arsenal, who are now in the semi-finals of the cup.
"It's going to be a pretty tricky schedule to manage, so we have two weeks off and then we're going to have to play three games in a week when the opposition won't have had to do that.
"That becomes a difficulty then with the physical capabilities of the players. It's a pretty difficult situation to manage, more difficult than we would like, but we have to think carefully about how to manage it."
Allardyce's immediate priority is Saturday's trip to Stoke, who beat Arsenal in their last game at the Britannia and have also won at home this season against Chelsea and Manchester United.
"It's a real tough game for us because their home form has been very, very good, as it was under Tony Pulis," he said.
"I think they're fifth in the table in terms of home form, only losing two, so it shows you how tough the game is going to be for us.
"Everybody has to be at their best on Saturday. They've had a good rest, some time with their families then they've worked very hard this week to get ready for what they need to do on Saturday to get a good result at Stoke City."