The visitors were gifted the lead on 25 minutes after Carl Ikeme let a David Davis back-pass through his legs, but second-half strikes from Sylvan Ebanks-Blake and Kevin Doyle earned Wolves only their second home win in 15 attempts.
Saunders said: "I thought everything was going wrong. We looked lacking in confidence, we weren't sharp around the box. We weren't reacting to things and when the goal went in, it was a calamity goal.
"Carl has given David the ball, he just has to put the ball away from the goal. But he gives it back to Carl and he has to get something behind it but it has gone in, and then we lose Bakary Sako and David Edwards to injury.
"Our finishing wasn't sharp and, to be honest, I went in at half-time and had a go at everyone. I wanted some sort of reaction from them and I have to say that the character of the players has stood out yet again.
"Instead of laying down and dying they have come back and won the game. It was a big win. You have to keep your belief and you have to have the strength of character when the chips are down."
Ikeme was substituted at half-time, but Saunders insisted the goalkeeper had suffered a hand injury and could not continue.