After enduring the heart-breaking loss of a loved one, the 30-year-old was set on a path towards health and wellness.
In eight months, she would lose 11 and a half stone.
"I have never felt physically and mentally better in my entire life," reveals the Dubliner who underwent bariatric surgery last year.
"I am incredibly proud of my old self because she is the one that made the decision, and she is the one that persisted. I always refer to her as another person because she is the one who endured hard times - it is very difficult being overweight because people do look and people do comment."
Suffering with severe hypothyroidism, a condition which can increase the risk of obesity, the devoted teacher struggled with her weight for years, despite living an active and healthy lifestyle.
"I've had hypothyroidism since I was 11 years old. The doctors said it was one of the worst cases they have ever seen. My siblings are all thin, but I have always been heavier - I was the outlier.
"Two and a half years ago, someone really close to me passed away. When they passed, I went to my GP to get my blood pressure checked and I started crying. She said to me, 'Can you please take next week off? Do something you love and relax.'
"I decided to join Westwood gym. That was two and a half years ago and I have gone to the gym four to five days a week every day since. I also made the decision to give up smoking and drinking. I made all these amazing changes to my lifestyle but I still wasn't losing any weight.
"A year ago, my sister who is an anaesthetist said, 'You're so healthy and you are doing a great job, but would you think of surgery?'
"She was extremely kind because this is obviously a very sensitive subject to broach with someone.
"I said 'no' and then two minutes later I asked 'What would it entail?'"
After committing to gastric sleeve surgery in the Mater Private Hospital in Dublin, with a team of specialists including a dietician, an endocrinologist, a psychologist and a respiratory doctor, the operation surpassed Orla's wildest expectations.
"The expectation from my medical team was to lose five stone in two years, so for me to be down 11 and a half stone in eight months has been indescribable," she says.
But for anyone thinking surgery is a quick-fix remedy, think again.
"This is not an easy option," warns Orla. "An easy option doesn't exist. There is a sacrifice involved but it is worth it.
"I found the two-week, pre-op diet which is designed to shrink your liver ahead of surgery very difficult. I had to come off every bit of sugar, even sugar that is in fruit and carbohydrates. I lost 30lbs.
"It is a keyhole surgery, so they went in and removed 80 to 85pc of my stomach. I spent two weeks on just liquid and two weeks after that on a puree diet."
A fortnight later, the fitness fanatic, who continues to share her journey through her social media (@onieochagain), was back in work.
"All of my colleagues were so supportive and so kind," she recalls. "I remember I was in the staff room and one girl had a pizza and she said, 'Orla, I am so sorry, do you want me to eat this somewhere else?'
"I moved on to soft food and then after speaking to the experts about my nutritional needs, I now have a regular diet."
Having just recently celebrated her 30th birthday, Orla describes her mental and physical metamorphosis.
"It has been absolutely life-changing. I have never bought more clothes in my life, I had my 30th birthday this month and I have never wanted to take more full-length photos.
"Sometimes I look at myself and say, 'Who is that?' I have lost 16 dress sizes.
Speaking of the pervasive fat-phobia that exists in society, Orla hopes people will unlearn their bias towards people living in larger bodies.
"Before it was really difficult having people stare at you everywhere you go," she admits now.
"I went for meals and had strangers beside me comment on what I was eating.
"Maybe that has made me resilient but something that used to frustrate me was the perception that I was lazy. I am the busiest woman in the world. I never stop. The lazy narrative needs to stop now."
Underscoring research that has confirmed that a person's size is not an indicator of their overall health, Orla adds: "I would go and get blood tests done before losing weight and they would come back really well.
"My blood pressure was high, but I was living healthily and I went to the gym all the time. I walked the Women's Mini Marathon."
Since dropping the weight, Orla is still discovering her new body.
"It was like I was carrying a whole extra person," she explains. "I used to be on two blood pressure tablets and now I am on absolutely nothing. That has been huge. "
The surgery costs €13,000 upwards with more competitive rates available abroad.