Dean Smith's side have not won in 15 games and are currently just three points above the drop zone.
But the defender, 33, is confident the club will not be playing in League Two next season.
"We have to keep the belief and come out fighting," Holden told BBC WM.
"We're in a dogfight but there's no point feeling sorry for yourself.
"There are plenty of teams in all the leagues down near the bottom.
"The ones that end up being relegated are the ones feeling sorry for themselves and always blaming someone else. That's not what we're going to do.
"We have to look at ourselves. We're professional footballers, we're going to apply ourselves properly and we're going to stick at it.
"You've got to pick yourself up as quickly as you can, get your boots on, put a smile on your face and go and work as hard as you can. That's the only way to come out of it."