When he took a trip overseas in 2017 after a relationship breakdown back on the Gold Coast, he didn't expect to hit rock bottom while waiting for his mate outside a shop.
"I was really broken – I was so lost and felt like nothing could go right," he told Yahoo News Australia as part of the What's Up? mental health series.
"I thought this is why I always expect things to go wrong, because they always go wrong."
Standing in the shopping centre, Mr Kelly said he just broke down and started crying.
"I thought: 'This is so embarrassing, this big tatted Aussie guy crying'," he said.
"My ex had a two-year-old daughter and while I was standing there waiting for a mate I saw a build-a-bear shop and seeing that just made me start thinking about everything.
"I would go out with mates and party and rack up cocaine and not get home until 5am ... she didn't want that life around her kid.
"I realised I didn't have the willpower to deal with the struggles and addiction and had to remove myself from my comfort zone and start again."
Gold Coast FIFO worker's spiral into depression
It was around 2014 when Mr Kelly's mental health really began to suffer.
But after long struggling with feelings of loneliness, anxiety and depression, he could never pinpoint exactly where it started.
Working in underground mines for 15 years as a FIFO worker and spending much of his time with the same people, he began to become paranoid people were saying negative things about him or plotting to get him off their crew.
"I would leave a room and think everyone in that room was saying bad things about me like,'He's hopeless'," he said.
In reality, none of that was happening.
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Growing up in a loving family environment, Mr Kelly said there was no reason why he got to such a dark place of absolute loneliness and hopelessness.
"I never thought of myself as an alcoholic or drug addict, but in reality I now consider myself a fully functioning drug addict," he said.
A FIFO worker living on the Gold Coast, Mr Kelly would stay sober while away for work but would hit the booze and drugs hard during the weeks he had off.
With a six-figure income, Mr Kelly was still resorting to borrowing money off his parents, spending up to $1000 a night on alcohol and drugs.
"I got involved with the wrong people and then there were times where I would be lying in my bed uncontrollably crying, thinking that everything was going wrong," he said.
"I didn't think I had any self-worth borrowing money from my parents... it got to a point where I would douse my anxiety by having a beer or two, but that's not enough so you have three or four, and by time you have your fourth nothing really matters."
Mr Kelly continued to descend into darkness and during a stint in Rockhampton drove recklessly from one side of town to the other.
"If something happens, it happens," he said.
"That's the closest I ever came to doing something.
"I got to the point where I would sit there and think if I did do something who would be the first to notice? My parents would think I was on a couple of weeks' quiet time, my friends didn't know when I was working – I thought work would be the first to notice I wasn't there.
"That was a sobering point I came to."
How Nic Kelly turned his life around
Surrounded by bad influences who encouraged a party lifestyle of drugs and alcohol, Mr Kelly made the life-changing decision to move away from the Gold Coast to Yeppoon in 2017.
He then adopted a dog named Chloe, who he says saved his life, and is now married with a young 20-month-old son.
While he still has negative thoughts, Mr Kelly uses writing as an outlet to clear his clouded mind and pays more attention to the food and drink he puts in his body.
"I just started fresh, I went to the gym and it was me against the person I was yesterday," he said.
"I removed all the negative people and it was just me and Chloe. My wife then came along and she was so supportive and inspirational.
"I believe everything happens for a reason and she came along just at the right time."
Mr Kelly is sharing the story of his mental health battle to let people know it's OK to not be OK.
"I struggle with stuff every day, I know that everyone has dramas and they might not be as bad as somebody else but that doesn't mean they aren't bad to me," he said.
"Don't ever be ashamed of your scars. Those scars show life tried to take you but you're strong enough to stay here."
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