Skipper Jason De Vos says the Blues must take their opportunity to win a place in the Premier League via the play-offs over the course of the next few weeks, starting with Wednesday's home game with Cardiff City.
De Vos said: "This chance may not come round again. We must all realise this on Wednesday. Some of the younger players have not been in the game long enough perhaps to appreciate it.
"I am desperate for promotion and, with the bulk of my career behind me, it means so very much to me.
"We have got to grab the fantastic opportunity that is in front of us. We have to bounce back.â€Â
De Vos admitted his defence was at fault at Layer Road on Saturday, but felt that effort wasn't lacking: "We have to hold our hands up and take the blame for conceding two bad goals. Colchester had two chances - took them well and ran out worthy winners.
"We missed chances - we had enough to win - but we must take collective responsibility for that.
"There was effort and there was passion, but the manager was right to have a go in the dressing room at the end.â€Â
Striker Shefki Kuqi and midfielder David Norris are in with a chance of making Wednesday's game, although both are more likely to return for Sunday's derby with Norwich City.