He said: "I had the new fixture list put on my office wall and I got that scared of it I nearly took it down again."
Allardyce explained: "If we do OK in the UEFA Cup, we are looking at 50 to 55 games this season - and that doesn't include international matches or the African Nations Cup when five of our lads could be away for at least a month.
"At the end of last season, we put forward a number of 24 players as the minimum we needed for the new season. At the moment we have 18 in our first-team squad.
"We've simply got to get to where we need by the time the window closes on August 31 because if we don't do that we could be in serious trouble."