She had two happy and healthy kids with a third one on the way, a partner she adored and a job that fulfilled her - but one day, one single thought would change her life forever.

When I phone Sophie, it's the first time we've spoken at length since connecting over our joint experience - a mental illness often laughed-off as a quirk or a penchant for tidiness.

"I'm really glad you reached out to me to speak about this," she said.

Before beginning to retell her story, when asked if she was afraid of judgement or misunderstanding, she said, "Of course I am, but if I can help even one parent who is going through this, it will be worth it."

"I'll never forget that day," Sophie said. "I was sitting in bed next to my daughter and a thought popped into my head 'what if I inappropriately touched her or harmed her?' - I recoiled at the thought. I eventually got to sleep, but the next day everything got so much worse."

Sophie, of Mandurah, found herself waking up the next day consumed with the fact that she'd experienced that thought, she turned to her partner and her best friend for reassurance.

"I told my partner about the initial thought, and that I kept having thoughts like it pop into my head since. I told him I thought I was a monster," she said. "His initial response was disbelief, he said 'what do you mean you thought about hurting our daughter?'. And then I really started to wonder if I was a monster."

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The thoughts convinced Sophie that she was a danger to her children, despite never having harmed them before and she found herself avoiding being alone with them and having her partner bath and change them.

"My partner had to come home from work, I felt so unsafe."

What Sophie really had, that she was yet to discover, was undiagnosed obsessive compulsive disorder (OCD).

Her condition reached breaking point when she found herself considering self-harm.

"I was driving one day, after having to leave work because I was so bombarded by these thoughts - and I just thought, I'm going to drive into a tree."

After pulling to the side of the road and calling her mother in tears, Sophie was rushed to the emergency room at Peel Health Campus, where she was referred to the prenatal team. That was where she first heard the term "perinatal OCD".

"I was in complete hysterics telling the team about these thoughts - that I kept worrying I would hurt my kids because of them."

After talking to the Peel prenatal team, Sophie was met with a response she didn't expect.

"They told me that these thoughts didn't make me a monster and that what I was experiencing was common of OCD," Sophie said. "The way the media portrays OCD I would never have believed it could present this way."

The SANE Australia organisation states that OCD can manifest in many ways other than the popularised portrayal of cleanliness, including "fear of harm to self or others and intrusive sexual or violent thoughts".

"The more I started to learn about OCD and what I was experiencing, the more upset and frustrated I was about the portrayal of OCD in the media," she said.

"Every time someone talks about OCD it's being used as an adjective, 'I'm so OCD about my kitchen', which just completely takes away from the seriousness."

While friends and family were posting lighthearted OCD memes on Facebook, Sophie was unable to hold her children.

"I remember once, my daughter was sitting on my lap and she wanted me to hold her but I just couldn't, I was so afraid I'd hurt her. The thoughts kept popping in, 'what if I threw her off a bridge?', 'what if I hurt her?'"

The Peel prenatal team referred Sophie to her first psychologist, and she set out on a journey to find the right specialist.

After a grueling experience leading up to her diagnosis, Sophie spent time trying to find a therapist who understood OCD.

"It is so difficult to find a therapist who specialises in OCD. A lot of people see patients with OCD, but not many really specialise in it."

Sophie's world was changed forever when she finally found an OCD specialist in Perth who offered cognitive behaviour training (CBT) and exposure and response prevention (ERP).

"After three sessions with this therapist I was on the way to healing, she said. "He taught me how to see the thoughts for what they are - intrusive and false."

Anxiety Australia explains that exposure and response prevention is part of CBT for those suffering with OCD.

"The OCD sufferer has to expose themselves to the thoughts, situations, objects and images that trigger anxiety and/or obsessive thoughts. However, they must refrain from responding to their anxiety or obsessions with a compulsive behaviour."

By allowing the thoughts to pass by without engaging with them or giving them any weight, Sophie saw her symptoms begin to dissipate.

"I'm not 100 per cent free of these thoughts and OCD isn't something that just goes away, but I'm in such a better place," Sophie said. "It is so important that people understand the different ways that OCD can manifest and that people stop making light of a serious illness."

Sophie said her goal with sharing her story was to make sure any parents who might be reading it who have been suffering in silence over thoughts they can't share can realise they "aren't a monster".

"You hear after people commit suicide, people saying 'I didn't see it coming,' and I think 'of course you didn't' - how could someone share thoughts like this? How could they get help? How would people know that this is OCD and they aren't really going to harm their children?"

Sophie welcomed her third child with her partner and their little family is happier than ever.

"I'm on the road to recovery. My partner has been amazing and has been learning about OCD."

Sophie's parting message was that OCD can be a deadly illness, and should be treated as such.

"I never thought I would suffer from a mental illness like this - I never understood OCD. It is so important for people to share their stories that might help someone. That's why I've shared mine."

If you or a loved one are struggling with a mental illness, reach out for support.

Lifeline 13 11 14

Beyondblue 1300 224 636

*The names in this story have been changed due to widespread misunderstanding of intrusive-thought-based OCD