The Lions’ former boss Gary Rowett left the managerial role last month and Barrett is now trying to steer the side, who are sitting in 18th position in the Championship, until a successor is picked.
Millwall have played three matches under Barrett but they have yet to find a win, recording two draws and one defeat.
The Lions are set to face high-flyers Southampton on Saturday and have been handed an injury boost as key figures Ryan Leonard and Shaun Hutchinson are about to be back to the squad ahead of the match.
Barrett stressed that he is relishing his tenure as a caretaker boss at the Den and players are also working hard under him.
But he pointed out that key players’ injuries made him play the team without significant options in previous matches, which was a notable problem he faced.
“There has been a lot of encouragement with the performances and I have been delighted with the lads’ reaction”, Barrett told the South London Press.
“They have really bought into it and they are working their socks off in training.
“They have really come together as a group.
“I am not one to make excuses but the squad has been thin as well.
“It has been quite difficult in that respect.
“It has been good to have a full week.
“Hopefully, we get a few bodies back to make us a little bit stronger.“
Millwall are hoping to hurl tough questions at the Saints on Saturday but the task is difficult.
