Town's play-off hopes look all but finished after they crashed to a 3-0 defeat at Shrewsbury on Monday.
But Barker has reminded his side how well they have acquitted themselves in their first season in League One ahead of Saturday's tough trip to MK Dons.
"We've dealt with a lot of things this season," said Barker.
"We'll make sure that the first season we've played at this level is as good as it can be.
"I'm disappointing we didn't win on Monday but it's important we recover quickly."