Andy Butler felt the way his team were beaten by Burton Albion showed that confidence is fragile within the group.
After a positive first-half performance, three second-half goals for the Brewers secured the win at the Keepmoat Stadium.
He said: “It was a story of two halves, in the first we moved the ball well and created things, but in the second we conceded goals which were so soft.
“Their first goal came from our corner so the work we had done on maintaining our shape wasn’t on show for that.
“You could see after the first goal that the players became deflated and that is just where we’re at right now.”
Butler changed formation to a 4-4-2 ahead of the game, and felt it worked for the opening 45 minutes.
He added: “We started brightly and with a purpose, it’s probably the best 45 minutes for a long time but in the second-half we couldn’t replicate that.
“We’ve not scored enough goals so it was in my mind to get two strikers on the pitch, it worked well in the first-half and we caused them problems.
“We gave the information at half-time and where we felt we could go onto win the game, I felt we didn’t use that well enough.”