"In all honesty, we can look at the whole season and say we weren't good enough because we have gone down, but we had a chance to make it a lot different by beating Bolton," says the England keeper sadly.
"Effectively, in the last 11 games, that one defeat has been the crucial turning point for the end of the season.
"We are not happy, but it is the course of the season that dictates whether you stay up or go down - and we weren't good enough, it is as simple as that.
"If the season was only 11 games long we would be happy, but it isn't and we're not.
"Over the summer everyone has got to have a good look at themselves and basically see where they have gone wrong, what they can improve, whatever - it is not good."
As for the future, he adds: "We will see. There is a big break now and I am sure there will be a lot of talk between the club and the players to see where we are going to go.
"It is a massive blow. We are all part of the team, and it doesn't matter who got player of the year - in fact I don't even know who got it this year.
"We have gone down as a team, we haven't been good enough over the course of the season, and we should be equally disappointed for every single player.
"There are a lot of questions need answering during the summer and we will look at them.
"Fortunately, Glenn is out of hospital and everybody is happy about that but we are one of the relegated sides and on a career portfolio that is one thing you don't want - but it has happened now."
Of the last day drama - and a brief glimmer of hope when the Hammers were ahead and Bolton only winning 2-1, he says: "Disappointment is the overall feeling because we have gone down. Unfortunately it wasn't in our hands and as long as Bolton won they were going to stay up.
"Birmingham made it a hard game for us, playing for personal pride, and fair play to them - but if we had won 3-2 we still would have gone down."
And Trevor adds: "The realisation does sink in about what it means to the club and it was a despondent dressing room."
Although the first story of a transfer request has already surfaced, Trevor insists there will be a measured approach to the challenge ahead.
"It is a time to reflect. There is no panic button being pressed in the East End - we have got two or three months in the summer when I am sure things will happen as we decide what we need to do," he says firmly.
"We need to try and deal with the financial implications but also try and keep the nucleus of the squad which will give us the opportunity to feel they start with the chance to try and bounce back."
He hopes the unwavering loyalty of the fans can be matched by the players and adds: "Obviously we have been very lucky in the past with how loyal the fans have been, and you feel for them on occasions like this, because they stay loyal during these difficult times.
"We need to give them something to shout about at the start of next season."
As for the rumours, he says: "That is not a surprise and there will be more but we have to sit down with the players, their advisors, and see what the situation is - but you hope that there will be some important players with us at the start of next season."
Trevor will play a leading role in the summer negotiations but insists his tenure as caretaker manager is over.
"Glenn is progressing well and is hopefully going to have his surgery later in the week," he reveals.
"I have switched to my boardroom hat now. When we had the games it was different but now we will be having meetings with the other directors and different people to see, as the weeks progress, what decisions we have to take - but it is a joint involvement now.
"I think it was easier years ago for clubs to keep more people and be in a position to bounce back. This time the financial implications are greater because the satellite money is not there - but there is no need to make early, rash decisions.
"We have to structure it so that we have got a short stay in the Nationwide. Leicester have done it this year and Ipswich just missed out.
"But the fact that we finished so far ahead of the other relegated teams doesn't really matter - you are down and everyone starts from scratch.
"It is not just about assuming we are in a position to bounce back - it is about proving it."
Meanwhile, Sven Goran Eriksson has named a 25-man squad to face South Africa, Serbia and Montenegro, and Slovakia this summer, which includes Trevor Sinclair and David James.