Brown said in her 32 years as a business owner, including 19 owning Mediterraneo Cafe ("The Med"), this was "up there" as one of the "scariest" times.
"It's been a huge shock and it's so scary. I never thought it was going to happen to me and I'm certainly not a naive business owner.
"When it does it's a huge responsibility just trying to deal with all the processes you need to follow, keep the cafe running as well as keep all my staff and customers safe.
"I don't usually work the till as other staff normally do that, but I'm having to bluff my way through it and it's a huge responsibility trying to keep the till records in order.
"Fortunately, some of my friends have been helping me out and I have also had some of my fantastic customers pitch in to do the dishes.
"I did a 15-hour day on Wednesday, and a 16-hour day the day before and the day I found out about my chef's positive test I probably cried for six hours."
Brown said she hadn't slept properly since finding out about the result.
"Today [Thursday] is my father's 86th birthday and I'm trying to get to Rotorua to see him. But I can't do that until I can close the cafe."
She said the past few years had been hugely stressful and this had added another layer of stress entirely but thanked those who had supported the business during a "very challenging time".