A Brampton family is trying to piece together the series of events that led to their 73-year-old mother being found slumped outside her car in a Georgetown, Ont. parking lot, three days after she left to go grocery shopping.

Susan Berry said her mother, Carole Berry, wanted to pick up cupcake mix before her grandchildren came for a Family Day visit and left her Hurontario Street and Elgin Drive apartment on Thursday morning to the grocery store.

When she failed to return home, her family reported her missing.

The Berry family, Peel Regional Police and dozens of volunteers spent much of the weekend visiting old homes, parks and churches, hoping Carole would turn up.

“I was really starting to prepare myself for the worst outcome,” Susan Barry said.

That was until Sunday, when a Georgetown, Ont. grocery store employee spotted the elderly woman in the parking lot, slumped on the ground outside of her car.

“I thought, ‘This isn’t right’ and then I said we should call an ambulance,” said Braeden Murray, who found Berry by her car. “I thought she had hit her head and she seemed a little dazed.”

Police believe Berry spent three full days lying on the cement of the parking lot.

“It certainly brought all our family together quite quickly,” Susan Berry said of receiving the call from police that her mother had been found alive.

“Certainly it’s a very happy ending to something that was very surreal and very traumatic for everybody… especially for my dad.”

Speaking briefly to CTV News Toronto, Berry’s husband held back tears describing the traumatizing feeling of losing his spouse.

“I don't know what I would do if it didn't have this positive outcome. I'd be lost,” he said. “I love her with all my heart and I'm really pleased that she's back with us again.”

How Berry ended up in the parking lot, more than 20 kilometres away from her home, remains a mystery to the family.

Susan Berry said her mother is unable to remember much of what happened and the family has been working with police and doctors to try and piece things together.

Peel Regional Police told the family that Carole didn’t use any bank cards during the period she went missing nor did she use very much gas from the time she left her apartment to the time she arrived at the grocery store. Investigators are also working to obtain surveillance camera footage from the grocery store parking lot to determine exactly how long Carole’s car was in the lot.

Susan Berry said the incident is “totally out of character” for her mother.

“It makes no sense. The hospital here is trying to do a work up on her because there are some signs of some physical problems with her brains – perhaps a stroke, perhaps a seizure, we’re not sure,” she said.

“She really must’ve just driven from one location to the other and been in her car or on the ground for that three day period.”

Aside from feeling a bit embarrassed about the situation, Susan Berry said her mother suffered some sort of knee injury during the ordeal but is otherwise “doing alright” and recovering in hospital.

“When we told her that the doctors were amazed at how she survived that incident – three days without drinking and food, out in the cold by her car on the ground – she really rallied around that thought, that she was strong and had the strength to survive,” she said.

With files from CTV News Toronto's Heather Wright.