The 23-year-old had been living the dream. She was an overseas tourism worker, who spent most of her time around the Caribbean.
However, as the Covid-19 pandemic began to spread across the world, Manwell ditched her job, packed up her life and rushed home before New Zealand's borders were closed.
Manwell donned a mask, gloves and long sleeves as she navigated through a London airport last month and was stunned to see so many travellers unprotected.
"People were giving me funny looks for being so protected."
During Manwell's second flight from Dubai to Auckland she noticed herself developing a dry throat. At first, she thought it might have been due to the altitude or air conditioning on the plane.
When she arrived in New Zealand on March 23 and her mother Sarah Manwell picked her up from the airport in a hazmat suit with goggles and a mask, Manwell initially thought the outfit funny.
Then she remembered there were eight other people living in their home, she knew why they had to be careful.
On arrival in Tauranga, the welcome home hugs were replaced by waves from 2m and Manwell's mother set her up a "glamping" tent in the back garden for her to isolate in.
After two days, she developed a fever and her throat began to swell up.
"I knew I should go and get tested, so mum and I suited up and went to the drive-through clinic at the Tauranga Racecourse."
Days passed and Manwell's condition worsened. A few days later, she got the call confirming her Covid-19 diagnosis.
"I burst into tears when they told me.
"I just had it in my head like, 'oh it'll never happen to me'."
Manwell said it was hard to come to terms with being one of New Zealand's few cases at the time. The next morning, the virus symptoms truly took hold.
Manwell said she was lucky, as a healthy 23-year-old, that her body was capable of handling Covid-19 but she said she understood how so many elderly or unwell people could die.
Manwell is now on the mend. She has slight congestion in her chest but is feeling a lot better.
A medical caseworker checks up on her and her family every day.
"The hospital has been fantastic ... if I get any signs of pneumonia, they told me an ambulance would come to get me straight away."
Manwell's family was in "complete lockdown" and could not leave the house for supplies or even a walk. With two boys under 5, this was challenging.
"We are all going insane here, but we know it's the right thing to do."
Once Manwell was symptom-free for 48 hours she was no longer considered contagious but she and her family would continue another two-week isolation to be safe.
"Being vigilant benefits everyone.
"I just want people to take it more seriously ... it takes one stupid person to spread it," Manwell said.
Manwell's message to others her age was that any party they wanted to go to during the lockdown was "not worth it".
"Think of your parents and grandparents' health."
Mum Sarah Manwell said the diagnosis had been "very, very stressful" as she had to make decisions in the "best interest of everybody" in the family.