She said she felt a huge pressure in her head and it felt like her body wanted her to "go deeper into the concrete floor".
Throughout it all she was aware of everything going on, and told her son who was with her that she just needed water.
As it happened, a nurse was due to visit Ms Emerson for an appointment - and immediately rang for an ambulance.
"She said I looked like I was having a cardiac arrest."
Ms Emerson said her body felt like "spaghetti" - but never did it cross her mind that she was having a stroke until the diagnosis a day later.
"It was just shock."
Ms Emerson was just 38 at the time of the stroke - one of about six New Zealanders under 65 who have a stroke each day.
While her balance has generally come right, Ms Emerson said she still had some mind blanks and initially found speaking hard.
Ms Emerson said with the support of the Stroke Foundation she had physical and language therapy, and when she heard the advertisements for Evita she decided it was the challenge she needed.
"I have to keep myself busy and motivated. That is what inspires me."
She said as a result of practising singing, her speech had improved and she was quicker to answer and speak with people.
"I've stepped out of my comfort zone. It's given me so much exhilaration. Yay, I did it! I went for it, and I got it."
In another step out of her comfort zone, she appeared on television show Family Feud last month. Her advice to others who have had a stroke? "Don't give up."
Next month, the Stroke Foundation, Health Promotion Agency and Ministry of Health will roll out a nationwide campaign - called FAST - to raise awareness of the symptoms of stroke and the need to respond quickly.
Signs of a stroke - FAST:
FACE - is their face drooping on one side? Can they smile?
ARM - Is one arm weak? Can they raise both arms?
SPEECH - Is their speech jumbled or slurred? Can they speak at all?
TIME - Time is critical, call 111.