Vale, who have won just one of their last seven games, fell 2-0 down to a Sean Clohessy penalty, earned for a foul by Darren Purse, and a Brett Assombalonga strike before Lee Hughes' consolation in the 63rd minute.
And Adams says their first target is the play-offs as they look to end a four-game winless run.
"Promotion seems a million miles away at the moment because we are having a bad run at the business end of the season," he said. "The first target is to make sure we get enough points to get into the play-offs and then go from there.
"It was very disappointing again and I'm fed up of saying the same things. We went two goals down and never recovered.
"We keep giving our opponents a lift at the moment. I have no complaints about the penalty and the second goal was also avoidable. We should have put the ball into the stand instead of trying to play.
"We had a go in the second-half. We had to go more direct and fight for second balls because we were getting no joy down the wings. It worked to an extent.
"After getting a goal we had chances and could have snatched a point, but it would have been snatched."