The Millers were beaten 2-1 by leaders West Didsbury and Chorlton to leave them eight points off top spot having played a game more.
And the joint boss believes it is now time to focus on their own results and not worry about what teams are doing around them.
“We will take it game by game and see where it takes us,” said Birch.
“It was disappointing to lose. It was a tough game and the conditions didn’t help the game, but it was the same for both sides.
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“Looking back on the game, a draw would probably have been a fairer result, but we missed some good chances.
“If you look at the table it will be difficult to catch West Didsbury now. They have to drop a lot of points which they haven't done all season.
“We won't worry about them, we are just taking it three points at a time.
“It's game by game now and we will not worry about who is around us.
“We were probably a bit guilty of getting into that mindset of who is playing who, who has beaten who and we took our eye off the ball a bit. But you live and learn and we will just see where we end up now.
“We have had a chat with the lads. It’s not been a great month and we have struggled since Christmas to perform.
“We’ve struggled to rack up wins. We have had some tough away games in what is a very tough league.”
But Birch insists New Mills still have their eyes firmly on the season aim of getting promoted.
They are currently ten points inside the play-off places with 10 games to go.
“At the start of the season a lot of people would have had us down for bottom half of the table,” added Birch.
“We set our own targets and the aim was to get promoted and be successful and that is still very much in our own hands.
“It will be tough, there are a lot of good teams and big clubs in there but our lads will come out fighting when their backs are against the wall, and that is all I can ask for.
"We have lost some big games but it is going to happen with a young squad. I’m always proud of the lads.
“There are plenty of points to play for and teams with us and around us will all drop points on the way.”