Harry Maguire put the Blades ahead with just over a minute gone and when Francois Zoko was given his marching orders midway through the second half for dissent there looked like being only one winner.
However, the Blades failed to press home their advantage and Alan Judge gave County a much-needed point with a late leveller.
Wilson said: "I'm frustrated as we didn't make our numerical advantage pay and second half we didn't play anywhere near like we did first half.
"First half we played with good tempo and even with 11 men we pressed the ball well but second half we didn't do that nearly enough and let them back in it.
"There is a nervousness about us at the moment in about three or four areas and whether that is the pressure that is on us I don't know.
"We have to play through it and get on the ball and play to our strengths. Unfortunately there are one or two who are struggling at the minute, I have to say that.
"We've got to get back to basics. There is a fear of making the wrong decision. It is frustrating as the league is there for the taking and we have to start making really strong inroads into doing that."