At 7 months pregnant, Nivek felt a 'firmness' in her breast. Then she got a call from her GP.

Motherhood can bring out strength a woman doesn't even know she has. 

Nivek Johnson just found hers, after being told the worst news of her life. 

While pregnant with her third baby boy, the 37-year-old was given an advanced cancer diagnosis.

Watch: Like Nivek, a 35-year-old woman shares what it's like to battle cancer while pregnant. Post continues after video.

Instead of falling into the depths of despair, a fire was lit in her belly alongside her unborn baby.

"I went into Mumma Bear mode… I have two other children already, getting that diagnosis - even though pregnant - knowing I have them, spurs me on," Nivek says. 

"I want to have all the treatments, I want to see them grow up. I've got to get through this."

A misdiagnosis.

Nivek's third pregnancy was tracking along the same as her first two with sons Arlo, six, and Remy, four. She suffered minimal side effects, and all her scans were normal.

But at 33 weeks, everything changed. 

At home in Canberra, Nivek felt a firmness on her breast. It didn't alarm her; she thought it might be a blocked duct. 

Being a nurse, she got it checked anyway. Nivek walked out of that doctor's appointment with antibiotics for mastitis—an inflammation of breast tissue, usually occurring in lactating breasts.

"I was misdiagnosed with mastitis, because of the fact I was pregnant," she says. 

"I had no other symptoms for mastitis—no redness, no fever, no heat."

Still feeling the firmness Nivek tried massage, and hot and cold presses, but nothing helped so she went back to the doctor who gave her a second course of antibiotics. 

Feeling frustrated, Nivek ended up on 'Dr Google', doomscrolling. She returned to her GP to push for an ultrasound. 

Finally, she was referred to another doctor who told her, "I don't think it's mastitis."

"It's really aggressive."

Nivek was sent for a mammogram and ultrasound which uncovered a mass. A biopsy confirmed the nightmare results. 

While driving, she got the call, but her GP decided to make her wait until she got home. 

"I knew then, when she said that. I got home and said to my husband, 'The GP is going to call back, I don't think it will be good news'," she recalls.

The diagnosis was triple-negative breast cancer. Nivek was two months away from giving birth to her third son. 

"I was told it was really aggressive. It was a lot of shock, very overwhelming," she says.

In the six weeks between feeling a firmness to diagnosis, a mass had grown.

"It had gone from nothing to a large tumour. It's such a fast-growing cancer," Nivek says. 

At 33 weeks pregnant, Nivek had no time to feel sorry for herself, she started chemotherapy while her baby was still developing, to ensure her best chance at survival.

Nivek in one of her chemotherapy sessions. Image: Supplied.

On July 3, she finally met Felix via a planned caesarean at 38 weeks. The strongest emotion in the delivery room was relief.

"He didn't have two heads or a tail, I had wondered, 'Did the chemo hurt him at all?', he looked perfect, it was pure joy," she says. 

"During pregnancy, I was in such preservation mode, I felt like I continued that drive... I thought 'I can't fall apart right now'."

Felix is now at home with mum and his brothers and has been an "absolute dream" only stirring for food and cuddles.

Nivek with her sons and newborn. Image: Supplied.

One of the hardest parts for Nivek has been losing the chance to breastfeed.

"I had to grieve that part of the journey, I did get 12 hours. But then I had to stop," she says.

"But the flip side... it means anyone can feed him and it takes a load off me. I don't feel guilty, if I have to lie down, I know he's safe and growing."

Talking to Nivek, you can hear her smiling, she speaks with positivity and grace.

Her mindset is no fluke. Nivek isn't a stranger to down days or the cruel pull of dark corners of the mind. 

She fell into the unforgivable grips of post-natal depression after her second baby four years ago and has worked on her mental health since then.

With this history, there was always a risk of slipping back into that place in her third postpartum. And now with a cancer diagnosis, it would seem inevitable for some.

Nivek says surviving her "horrible" experience with post-natal anxiety and intrusive thoughts gifted her with life-changing tools to be present and grateful.

"This time we know what to look for, if I feel like I could be heading that way, I am able to nip it in the bud," she says. 

"[This diagnosis] is something I cannot change, it will be a memory someday to look back on. Not a great one, but it's easier to be positive than it is to be negative."

The Johnson family is focused on healing and is a "no-fluff" unit. They have been truthful with their older sons about Mum's sickness. 

They know she has cancer and a "sore booby". Nivek even made light of her middle son's disappointment in her hair not falling out, because he wanted to shave his as well.

Her biggest challenge is the chemotherapy side effects—not because of what it's doing to her, but what it's taking away.

"I get tired, I'm not as active as I was. I want to run and kick a ball with them... Sometimes I can't put the bigger boys to bed... Seeing the disappointment in their face, it's crushing," she says.

Listen to this episode of The Quicky where we talk about what chemotherapy does to your body. Post continues after podcast.

Nivek thanks her support network, including her QLD parents who have moved in, for keeping her upbeat as she faces a gruelling regime of chemotherapy, surgery and radiation.

Despite the unknown path ahead, a future with her boys is Nivek's strength to keep going. 

"I am the nurturer, my boys love my tickles to sleep, I want to get well, I want to get better, and get back to what we were doing," she says.

A GoFundMe page has been set up to support the Johnsons, which has raised more than $31,000 to help Nivek’s juggle with postpartum and cancer treatment. 

Read more of our personal stories about Cancer:

• 'My symptoms were dismissed by doctors. Then they felt something "the size of a full-term baby".'
• Vanessa noticed there was blood in her stool. She knew it wasn't a good sign.
• When Rhiannon was pregnant, doctors told her she had hemorrhoids. The truth was far worse.

Feature image: Supplied.