The Riversiders face a fourth consecutive away trip when they travel to AFC Darwen on the back of a 5-1 defeat at leaders Lower Breck last weekend.
Having strung together four consecutive league wins during December and January, Garstang have now lost their last three matches.
It means they go into Saturday’s game 17th in the North West Counties League’s First Division North table, only three points clear of bottom side Steeton.
“A lot of home truths need to come out I feel,” Cookney told the club website after defeat at Lower Breck.
“A lot of players need to look at themselves a little bit.”
Alan Coar had given the Riversiders the perfect start on Saturday with the opening goal after 11 minutes.
However, two goals in 10 minutes from Stephen Milne and Louis Austin saw Lower Breck in front by half-time.
Garstang were still in it going into the final quarter-hour but Luke Duffy put Lower Breck 3-1 up before two late goals in as many minutes from Jamie Henders gave the scoreline a one-sided appearance.
Cookney said: “I thought, second half, we came out and played well until they got the third.
“Then, the last 10 minutes, heads went down but you could tell they (Lower Breck) are probably going to win the league.
“I was disappointed in the way we conducted ourselves today. I feel we’ve lost the game with second balls, they won everything.
“Their third goal, which was very well taken, they were on the edge of the box ready to pick up the pieces and none of us were around them.”