"I had support from ACC for a while, but they encouraged me to get back to work. And I thought, 'I should be ready to get on with it'. But it was too much, too soon," Lee said.
Lee said he has not received any support from ACC for over 10 years - financial or otherwise - nor the understanding required to easily survive, let alone thrive, as he'd once dreamt.
This is the sad nature of living with an invisible disability.
Lee said if it weren't for the support of his whānau, and the Brain Injury Association, he wasn't sure how he'd be coping.
"I thought I'd have a family by now," said Lee, who is in his late 30s.
"Kids, and a wife, and a career.
"I've had some relationships since my injury, but they all just eventually fell apart."
According to Dr Alice Theadom, professor of psychology and brain health at Auckland University of Technology (AUT), that was a common story among people who'd suffered even mild traumatic brain injuries (MTBIs); Lee's was certainly classed as serious.
Concussion is a form of mild traumatic brain injury, and the term commonly used in a sport context.
Theadom said according to ACC records, there were just over 1000 MTBIs in Northland per year.
"MTBI's can change a person's sense of self, and have a profound impact on their relationships," Theadom said.
"People often talk about their partner almost having a different personality following a MTBI.
"It's not uncommon to become more reserved, and to have less confidence and lower self-esteem - because they're still struggling with this injury everyone expects them to have recovered from."
According to Vikki Herdman, a liasion officer at BIA Northland, 5-7 per cent of concussions will turn into a serious, long-term brain injury - and this been the case since the 1980s.
"Because it's an invisible injury, people think it should just stop having an effect," Herdman said.
"It really is a silent epidemic."
Theadom's research has looked at how MTBIs affect one's ability to understand social situations.
"Processing speed is hugely affected, so making sense of everything you're seeing and hearing, and deciding what's important, becomes very challenging."
"It can be far more difficult to pick up on nuances like sarcasm, which has a profound impact because it can lead to misunderstanding and conflict."
She said maintaining employment was another challenge.
While 98 per cent of people with MTBIs returned to work after their injury, Theadom sought to discover what happened in the longer-term.
"We found that, four years after their injuries, many had reduced working hours, changed to a back-office role - requiring less social interaction - and generally changed their responsibilities to focus on their strengths," she said.
"It affected some people's ability to support their whānau. Reduced hours - and pay - is challenging for a main breadwinner."
Theadom said many people with MTBIs don't go to hospital, so it's impossible to estimate the scope of impact.
"As many people with MTBIs have also sustained more obvious injuries, brain injuries are not always diagnosed," she said.
"The onus is on the patient to go back, so if they can't afford that or don't know they're meant to, that's another barrier to accessing care," she said.
"Navigating our health system is one of the biggest challenges people face."
She said her team was working with ACC to improve access to support.
The current gap in care is being filled by the Brain Injury Association (BIA), which offers solidarity and practical help.
"People don't know who's out there to help, so we often put them in touch with BIA," Theadom said.
"If their claim has been declined by ACC, BIA can help with advocacy and education - like practical tips and tricks to help them with daily tasks.
"They also provide essential support for those no longer accessing ACC, as that support only lasts one year.
"It can really have a long-term impact, so people need long-term support.
"That's where there's a real need in our community."
At a recent meeting of the BIA's Kaitaia support group, members said it was common for people to expect them to "just get on with it after so long."
Family members, friends and co-workers simply could not understand their experiences.
"Here, we're all the same. When I share what's been going on for me, everyone just gets it," said one member.
Her statement that "we just accept each other for who we are now" was met with gentle smiles and deep nods from around the room.
BIA Northland's Herdman said the monthly support group meetings were well-attended by the same clients month after month.
"Support groups are safe spaces where people are comfortable expressing themselves in an understanding environment.
Herdman said clients did not pay to attend support groups, and accessed care regardless of whether they'd paid a membership fee ($5 per year) or not.
She said BIA Northland needed $172,000 per year to run with its current staff of three.
"We receive $1400 per month from government contracts, and the rest of the money required to run this organisation comes from grant providers, fundraising events and donations."
She said the ongoing reduction in pokie machines - which was a source of funding - meant BIA's funds were on the decline.
"I would love a budget of $250,000, which would give us the capacity to provide more services, and to employ a fundraising person to concentrate on that aspect.
"And we wouldn't have to be so concerned about potential closure."
To make a donation, contact Mandy at northland@brain-injury.org.nz or visit: givealittle.co.nz/org/bianorthland.