Elisa Frank was 19 when asylum seeker Ahmad Otak killed her 17-year-old sister, Kimberley, and friend, Samantha Sykes, 18, in a frenzied knife attack in Wakefield in March 2012.
He then abducted her in a failed bid to escape the country but was arrested and later jailed for at least 34 years.
Now 22 and living in Leeds, Miss Frank has penned The Borderline Diaries – a semi-autobiographical account about the murders and her recovery.
She said: “If I didn’t have writing to focus on I would be lost. It’s all I do, it’s something I use to get through.”
Miss Frank was groomed by Otak when she was in care. They had a turbulent relationship during which he threatened to kill her if she left him.
A month after she ended the relationship, he turned up at Kimberley Frank’s flat with a kitchen knife and stabbed her 15 times in front of her sister.
The sadistic killer licked blood from the knife and spat at her body after stabbing her.
Otak then tied Miss Frank up and made her ask her friend Miss Sykes to come to the flat. When she arrived, he stabbed her repeatedly.
She suffered 32 stab and slash wounds.
Miss Frank said: “I still have nightmares every single night. It started out being about the event, then sometimes I’d see Kim as a ghost.
“I try not to think about it during the day. If I do, it’s too overwhelming.”
Miss Frank spent several months in hospital and was diagnosed with post-traumatic stress disorder and borderline personality disorder, which gave the book its title.
She describes the account, which runs to 53,000 words, as creative non-fiction rather than autobiography, but admitted the prospect of having her story made public was scary.
She added: “Me and my sister used to write a lot. We used to talk about getting published, so I feel like this is for her.
“When you write about someone, it keeps their memory alive.”
The Borderline Diaries, published by Local Legend, will be available later this month priced £9.99.
To find out more, log on to www.local-legend.co.uk