The buzz of a game, the adulation of fans and the money stopped almost overnight
In its place was a desperate void.
"You end up in a spiral to a pit that's very tough to get out of," the former Republic of Ireland striker said.
"It's often been referred to as a death within your life."
For many it is hard to believe that today's multi-millionaire footballers can end up in such a bleak place.
Quinn admits sympathy may be hard to find due to the amount of money in the sport - but the statistics he highlights are hard to ignore.
Problems with alcohol, depression and anxiety are well documented - George Best, Paul Gascoigne and Quinn's former team-mate at Arsenal Kenny Sansom to name just three.
"Almost half of ex-professional footballers from the Premier League visit bankruptcy and 33 per cent end up divorced within three years of retirement," says Quinn.
"There are so many ex-players who inevitably become a pale shadows of their former selves."
That is why Quinn has set up a new initiative called Catch A Falling Star, which forms part of new consultancy company Fleet Street Sport and Media.
The aim is to educate athletes in their psychological well-being before they retire, a moment Quinn says they are totally unprepared for.
A group of experts will provide a stark voice that a player will listen to and hopefully learn from
The experts include financial advisers, life-coaches, counsellors, medical experts and, crucially, players' wives.
"Sports stars don't want to tackle retirement issues early," said Quinn.
"The fact of the matter is they should have prepared far better and far earlier for the end of their career
Our group wants to be that provision."
Putting together such a group does not come cheap and there will be a cost to the player, but Quinn says it should be seen as being just as important as private physical healthcare.
It is not just footballers
The Professional Cricketers' Association has recognised that issues arise when players retire and, according to a new survey, nearly all struggle when their careers finish with 16 per cent experiencing feelings of depression and despair in the first year after retiring.
Quinn, 49, returns with brutal honesty to his own journey.
"I had a tough first three years," he admitted.
"The first year was a real bad year after I quit
I had not prepared properly
It felt dark
I did not want to see anyone
I did not want anyone to make eye contact with me.
"It was tough getting out of bed sometimes
Everything suffered
The relationship with my family and friends."
Quinn admits his big break was when he became involved in purchasing another of his former clubs, Sunderland, in 2006.
"I got my mojo back, I got the drive back and now I love meaningful diverse challenges," he said.
Some are not as fortunate
But Quinn is hoping he can go some way to helping them avoid the pitfalls that lie in wait.
Source : PA
Source: PA