The 33-year-old rued his side's convincing loss at the hands of Bradford City in their League Two showpiece final on Saturday, with midfielder Chris Hackett similarly disappointed
The 33-year-old, who is also the chairman of the Professional Footballers’ Association, has been in the play-offs before when he won promotion from the Championship to the Premier League in 2009 with Burnley.
However, goals from James Hanson, Rory McArdle and Nahki Wells ensured the Cobblers skipper would experience things from a different perspective on this occasion and Carlisle admits it prompted a "horrible" feeling.
|15/1||Watford are 15/1 with BetVictor to beat Crystal Palace by exactly three goals in the Championship play-off final
"The best way to get promoted is a play-off final. They are the best thing in football – play-offs, but it’s the worst way to end the season if you lose.
"After 27 minutes, it was just about pride for us. You have to consider where we’ve come from; last season we were almost relegated.
"To get into the play-offs is an achievement in itself but you see all your family and friends here and you feel like you’ve let them down. Hopefully we’ll not need the play-offs to go up next year.”
Midfielder Chris Hackett shared Carlisle’s disappointment and was at a loss as to why Northampton were unable to deliver on the big stage after undergoing ideal pre-match preparation.
"We couldn’t deal with them," the 30-year-old said, "I don’t know what we could do – we prepared in the best way possible.
"Before you knew it, half an hour was up and we were 3-0 down. All the boys were desperate to win and do what we can do but I don’t know.
"I’ve lost in the play-offs previously as well and I’ve won so I’ve come from both sides. It’s fantastic when you win but you’ve got to really pick yourself up when you lose."
Hackett did see cause for optimism, however, suggesting that the strong team spirit within the current squad means Northampton can use the experience of defeat as a springboard for greater success.
"You feel like you’ve almost been relegated but that’s the thing you have to look at – you haven’t actually and we’ve come a long way, getting to Wembley with a good season and a good points total,” he continued.
"We pushed on after quite a slow start. It’s been a great season all round and we’ve got a great set of boys.
"The one thing I have seen is we’ve got a great team spirit and if we keep the core of the bunch together and add a couple [of players], we can definitely build on this and we’ve got to keep our heads held high."