Richard Keogh and Chris Martin gave the home side a commanding lead before Jeff Schlupp pulled one back, but County survived a late barrage of pressure to earn their first win in nine matches.
"We didn't play very well and we are in a bad run of form at the moment," said Pearson, whose side remain sixth in the Championship despite losing three of their last five games.
"There were too many mistakes. We didn't play with any authority in possession and conceded two poor goals.
"We huffed and puffed in the second half and had quite a lot of possession but didn't show the quality to rectify the situation.
"We have got to get back to basics during the international break because we have worked too hard to get ourselves in a decent position to put it in jeopardy.
"There are still opportunities left for us and we have to keep our nerve. One of the disappointments today was that we have allowed the game to pass us by."