Melissa initially blamed her irritating symptoms on stress from her divorce.

The mum from Bathurst in NSW, then aged 30, was suffering from back pain and morning nausea and, as a single mother of two young children, she was programmed to ignore it.

"At 3am, I started to feel sick, I just thought I had gastro," Melissa told 9news.com.au. 

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"To be honest, I'd been in my job three months, so I didn't want my employer thinking I was having a long weekend, so I'd gone to the doctor to get a doctor's certificate."

Visiting her GP that day may have been what saved Melissa's life.

She was taken to the hospital for some blood tests after feeling light-headed, and by 2pm that afternoon, she had an unexpected diagnosis.

Melissa's pain was caused by a solid pseudo-papillary mass, a rare pancreatic tumour.

"It was the size of a large grapefruit, so it had sort of started to crush other organs, opposed to reaching out like other cancers do to the organs, so it wasn't spreading," Melissa explained.

The tumour was located at the head of her pancreas.

Her doctor said if it was sitting anywhere else, she would have had "two and a half weeks to live".

Do you have a story? Contact reporter April Glover at Google Play.