The 3-0 defeat to Peterborough on Saturday was City's third of the campaign and saw them drop into the relegation zone
Summer signing Pack knows Sean O'Driscoll's side have to up the ante quickly.
"Things have to start changing now," he told the club's official website. "Maybe we have to work harder (and) perhaps get back to basics to try and make sure we win a football match.
"Something's got to change because we can't keep giving opposing teams a headstart.
"We're all disappointed with the start to the season we've had. We didn't expect it to be this way."