Barnsley will play Third Division football next season after failing to beat Middlesbrough.
The Reds went down 3-1 at the Riverside - compounding a miserable season.
Danny Wilson said, "We started to believe in the second half but sadly we made a mistake. This isn't about one game it's about all season."
"To prolong it for so long when we were constantly written off is a credit in itself. It'll take a bit of getting over but we will.
We'll start planning for next season. The boys are hurting like mad. One thing is very clear - it needs starting again.
"There'll be a lot of changes, I'm sure, but it'll be for the better.
"You can't fault the boys. Certain times in the game you need that quality in abundance and we haven't got it in key areas.
"It's been a pattern and we've not scored enough goals. That's been the main problem. It's a horrible feeling.
"Without the fans we probably would have folded before. They're true fans. It's up to us to produce and win games because that's what the fans deserve."