The Bulls host Northampton on Tuesday just days after blowing a 3-1 lead to lose to Burton Albion at Edgar Street.
"It's unacceptable as far as I'm concerned and everybody is in tomorrow morning," Trewick told the BBC straight after the game.
Hereford are currently 8 points behind the Cobblers albeit with 2 games in hand.
They were 3-1 winners at Sixfields at the beginning of December, despite a first minute strike for the home side from Ryan Gilligan.