The Magpies' six-year tenure in the top flight came to an end as they missed out on survival to bitter rivals Sunderland.
"Last season I kind of felt ashamed at how the team were playing, and the results," Colback told The Chronicle. "You'd get support and people saying: 'Come on, good luck'. But you were not performing with the team you grew up supporting. It was the worst-case scenario.
"It is our job to perform, and we didn't and got relegated. As a player I get paid to do this and as a player you do feel ashamed walking around. This area, 95% support the team. It is not like London when you can be invisible.
"It was hard for it to sink in - it probably didn't until we came back and the fixtures came out. You weren't seeing the Man Citys and Arsenals, instead you're seeing Championship sides. That's when it hits home. We let everyone down last year, we know that, but we're trying to redeem ourselves and we're trying to do that the best we can. It was a really disappointing year but we are trying to restore pride."
Colback has featured 10 times in the league, with victories in nine games, under Benitez so far this season.