Denise Clark, 34, said her life was made 'absolute hell' when she was given the news two years ago.
She frantically spent £10,000 on treatment at an alternative therapy clinic in Spain, hoping to prolong her life, and went on what she thought would be her last summer holiday with her family.
But after feeling suspicious about how well she was feeling, Denise demanded another scan at the Aberdeen Royal Infirmary – which revealed the growth on her pelvis was not malignant after all.
Now, after starting proceedings against NHS Grampian following the misdiagnosis, Denise has settled a claim for a five-figure sum.
Before the blunder came to light, Denise focused her energy on giving her children happy experiences and started creating 'mum memories' to leave to her boys, Harvey, 10, and Luca, four.
She said: "I didn't know if I was going to end up dying in a hospital or if I would be at home or how it would actually happen.
"I wanted the boys to have fun times and lots of mum memories, like playing football together or having a barbecue. Nothing that cost a fortune."
She added: "I planned my funeral and wrote farewell notes to my boys. It was heartbreaking but I had to do it for my family. No one should have to do that if they don't need to."
She said she regretted how quickly her eldest son, Harvey, had been forced to grow up, adding: "It has been hard on him and he has just been forced to deal with so much at such a young age."
Her mistaken diagnosis was just one of several shortcomings in care she received at Aberdeen Royal Infirmary.
In 2009, while nine weeks pregnant, she was referred for a colposcopy – used to detect cervical cancers – after concerns were raised over bleeding.
Despite the referral, she did not have the test for another five and a half months.
At this point the cancer was so far advanced her baby was delivered early so treatment could be started.
She said this deprived her of time to bond with her newborn son. While he was in the neonatal unit, she was receiving such strong doses of chemotherapy and radiotherapy she could not even hold him for fear of contamination.
She was told she was given the biggest dose of radiation allowed in a lifetime – but it was enough to halt the cancer.
But in November 2011 she began to experience more bleeding and was told it was due to a huge growth on her pelvis and the cancer had returned.
It then took two years before specialists confirmed last December the recurring health problems were due to internal damage caused by the high levels of radiation and chemotherapy she received.
Recalling the moment she was told there had been an error, Denise, from Sheddocksley, Aberdeen, said: "The doctor was there with the test results and my mum burst out crying. I just started to laugh. My mum said 'how can you laugh', but it was all out of relief.
"I got home and said to my son, 'Harvey, the doctors made a mistake, they were wrong'.
"His little face just lit up and he was hugging me the hardest he has ever hugged me and said he never wanted to let me go."
The mum insisted she was full of praise for many of the medical staff at ARI x-ray unit, but said she had been 'let down' by NHS Grampian.
She said: "It wasn't just one department which got it wrong, it was multiple departments. They made mistakes time and time again."
Denise, whose marriage broke down because of the stress, added: "Hearing them say it was a mistake was amazing and there is a future now, but it doesn't give me or my kids back the two years of our lives that were made absolute hell.
A spokeswoman for NHS Grampian declined to comment on Denise's case.