Now, the 20-year-old is on the road to recovery - and is planning her dream wedding.
She is a picture of health as she talks from the Barrhead, East Renfrewshire flat which she shares with fiance Rab O'Rorke, 27, and which is crammed with dozens of get well cards from family and friends.
She said: "I moved here from Bishopton 18 months ago and in the whole time I've been here, I haven't been out the door."
Practically housebound and attached to a ventilator, she relied heavily on Rab –who uses a wheelchair due to spina bifida – to care for her.
"I couldn't wash or dress myself," she said.
"I only managed a bath twice a week as it was such an effort.
"I used to put on make up and do my hair every day, I always made sure I looked good but it got to the stage that I couldn't even do that.
"I felt I had lost my dignity not being able to do anything for myself."
Louise was diagnosed with cystic fibrosis when she was aged four. CF is a gen- etic disorder which causes the lungs to be clogged up with a thick, sticky mucus.
In spite of all the medication and daily chest percussion therapy, she never let her condition get in the way, learning to drive when aged 17 and studying for an NQ in photography.
But in 2010 she contracted pneumonia and spent seven weeks at the cystic fibrosis unit at Glasgow's Gartnavel General Hospital, after which she was put on 24 hour oxygen and the waiting list for a lung transplant.
Undeterred, the brave teenager carried on, oxygen tank in tow, hanging out with friends and going to concerts.
Later that year, she met Rab on a night out.
He said: "I had seen her before at gigs taking photos, she would be carrying her oxygen around with her, but I never looked at her any differently.
"That night we started talking about music and tattoos, things we were interested in and we just clicked."
The couple remained friends for a while before they started dating and eventually moved in together.
Waiting patiently for a lung donor to come along, Louise fell seriously ill again in September last year and was rushed to intensive care at Gartnavel.
It was then that Rab decided to pop the question.
He said: "My friend got some ring gauges and we asked the nurse to get her ring size.
"She told Lou she was measuring for swelling due to the steroids."
Louise said: "I didn't have a clue what was going on.
"I was so happy when Rab proposed, all the nurses were in on it.
"I was hooked up to the heart monitor and when he asked me to marry him it started beeping and they couldn't shut it off!"
She was eventually discharged from hospital and three times came close to being linked with a donor,. However, these all turned out to be false alarms and there was no match.
Louise said: "It was quite frustrating because you build yourself up to it.
Rab added: "It was hard, Lou would put on a brave face but I was devastated for her."
Suffering with high carbon dioxide levels, Louise was admitted to hospital again in May this year, beginning a desperate wait for a transplant.
When she was informed a donor had been found she made the 150-mile journey to Newcastle's Freeman Hospital by ambulance, while Rab and Louise's mother, Anne, drove on ahead.
It was another false alarm once they arrived, but that was only the beginning of the nightmare.
Deteriorating rapidly, Louise was taken to ICU and deemed too ill to be transported back to Glasgow.
Surgeons tried unsuccessfully to put her on to a life support system for transplant patients, and then installed a Novalung, a state-of-the-art artificial lung device developed in Germany, that acts as dialysis, removing toxic carbon dioxide from the blood.
Louise said: "That was the most distressing moment -it was so uncomfortable.
"My mum told me she was so upset at seeing me like that, she had asked the doctors to let me die in peace."
Louise was sedated and given just hours to live. Then the family finally got the phone call they had been praying for.
Rab said: "Her mum alerted at 5am and told me we had to go to the hospital.
"I thought that was it, we had lost her.
"But when the transplant co-ordinator told us they had found a donor, I was so relieved - we had a wee cry at that point."
After undergoing nine hours of surgery, Louise woke up almost a week after being admitted, able to breathe independently for the first time in months.
She said: "The nurse told me I had had my transplant.
"At first the news didn't sink in but mum then came in and asked me how my new lungs felt.
"I was attached to lots of tubes and wires but felt better and wasn't gasping."
She's since made a speedy recovery, leaving hospital just three weeks later.
She's documented her experience through an online blog, Hungry for Life, and plans to return to college, as well as making plans for her upcoming nuptials.
" I can do things with Rab now - I have a new lease of life," she said.
And she's backing the Evening Times' Opt for Life campaign.
"It's brilliant," she said,"If someone has their reasons for opting out, they're the ones who have thought about it and would go to the trouble."
She said: "Unfortunately someone died - but in donating their organs they saved my life.
"The words 'saved my life' are used so lightly these days but in this situation they could not be any more sincere or true."