The Terriers, unbeaten at home, were unlucky to leave The Valley without any points after going down 2-1 at Charlton, but now lie 10 points behind the second-placed Addicks.
Clark said: "Now we must dust ourselves down and get on with it. We have to prepare ourselves for next week and the Leyton Orient game.
"We still want to get one of the three positions that will get us out of League One and if we continue playing like we did (at Charlton), we will win a lot more games than we lose."
Clark added: "But we have to sort our away form out. Even if a team wins all 23 of their home games it would still not be good enough to get in the top six if they were picking no points up away from home."