Sheridan said: "It would have been a different story if we had taken our opportunities in the first half, although I don't blame Lee Hughes for missing a penalty because that can happen to anybody.
"We were comfortable for 45 minutes but it all changed at half-time and I honestly can't explain why that happened. I have a lot of good players at this club and some of them can't even get in the squad at the moment but some of our passing was nowhere near good enough after Bristol Rovers went in front.
"The goals we gave away were diabolical and we need to look at ourselves as players and coaching staff if we want to finish in a play-off position.
"We started the game fourth in the table so confidence should have been sky high. No disrespect but we should be winning games like this. I expected us to up our game after controlling the first half but we shot ourselves in the foot and must do better."