Neil Thompson said the Owls’ 3-2 defeat to Luton at Kenilworth Road saw the best and worst of his team.
A Josh Windass brace had Wednesday in front after the first 45 but the Hatters bounced back to claim a win that seemed unlikely at the interval.
Thompson said: “That’s the best and the worst of us.
“First half, we were very good and it was a good reaction after defeat in midweek, we could have been more than two up.
“You have to guard against the other team being allowed to play, they came out and we didn’t get into any rhythm.
“We gave a goal away from a corner, then the other two goals we’ve had good possession in their half but given it away and we didn’t deal with the runners and the balls in the box.”
The Owls face Rotherham next at Hillsborough on Wednesday evening and caretaker boss Thompson said his team need to react.
He added: “You have to react, it was half a job today and we’ve been punished.
“If we want to survive in the division, we have to go on a run, the games aren’t going anywhere, there’s another one Wednesday and Saturday and we have to deal with it.”