With Darren Anderton missing on Wednesday, the boss fears more injury problems after making three enforced substitutions, added the the fact that Mauricio Taricco is facing a suspension.
"Unfortunately for us Taricco is going to be banned and we've got injuries as well," reflected Glenn. "Deano had to come off at half time with a slight hamstring, Ben Thatcher had an injury and Les Ferdinand's got an Achilles problem as well.
"We were down to 16 tonight anyway, after that we've got young kids who are playing in the reserves so we are absolutely stretched squad-wise. And we've picked up more injuries here.
"So we've got to lift ourselves and we're going to have to show character."
Glenn added that the conceding of four goals in three games was not helped by the fact that the team were short-handed and behind in two of them.
"We're disappointed at this moment in time, it goes without saying. The mood will be when we train that we're going to have to work hard and collectively go forward.
"Two of those games we had ten men and two games where we've been chasing it and we've been down. So I think that tells a story in itself.
"Certainly on Sunday I was very disappointed with the way we conceded four.
"When you've lost three on the spin you can't wait for the next game to put it right. It's not so much who you play against, it's the fact that we've got nine games left with Charlton on Monday."
Glenn admits that his forward planning could be hampered by further injuries picked up at Chelsea.