Justin Richards and Louis Dodds both hit hat-tricks while Marc Richards also got on the scoresheet as Phil Jevons and James Spencer netted consolations for the Shrimps.
Grew said: "I've never felt this bad after a resounding win and the players feel the same. The dressing room is in deadly silence and that takes some believing after you have won 7-2.
"To be honest I'm speechless because this season will go down in the history of Port Vale as `what might have been.' I'm gutted we won't be going to Barnet next Saturday with the play-offs still in mind.
"It was an incredible game to finish with at home. It was very open from start to finish and we could have won by a cricket score if we had taken our chances.
"We've struggled to score goals before and it was just like waiting for a bus - when one came a lot more came straight after. It was nice to put a smile on people's faces on the terraces because it has been a turbulent season, but it's impossible to hide the disappointment."
Source: PA
Source: PA