Michael Doyle said Sheffield United's players need to take their share of responsibility for another failed season at Bramall Lane.
The Blades will embark on a third season in League One next season after losing out 2-1 on aggregate to Yeovil in the play-off semi-finals.
"We have come up short again and it is disappointing," Doyle told BBC Radio Sheffield.
"We have to look at ourselves over the summer. The play-off defeat sets the club and everyone back another year.
"Personally, I'm gutted. I've been down for the last week. Sitting around thinking about it hasn't helped.
"I still have that horrible feeling in my stomach. I want to get back in training as soon as possible.
"Yes, we have to recharge the batteries, but I want to get back into training as soon as possible and prepare for another nine months of hard work."
The Blades sacked former boss Danny Wilson with five games of the regular season remaining and appointed coach Chris Morgan as caretaker.
Julian Winter has since returned to Bramall Lane as football club chairman and a restructured board this week drew up a seven-man shortlist for Wilson's permanent successor.