"I had got a lot of pain in my life, I was suicidal, homeless, I had left the armed forces, and lost who I was," she says. "I didn't have an identity."
She later discovered that her experience was far from unique, and now uses her experiences helping others going through similar difficulties, thanks to the support of the Landau Trust charity.
Teri, who lives in Staffordshire, was one of a number of people the charity has helped who met Princess Anne in Telford during a visit to mark its 25th anniversary.
Teri, 31, says she came from a troubled family background, but the Army brought structure and discipline into her life. This led to her feeling a sense of loss when she left for life on civvy street.
"At school I had been told what to do, and when I was in the Army I was told what to do, and now there was no-one there for me, and I had to stand on my own two feet," she says.
Her problems were compounded when she later became a mother, and suffered from postnatal depression.
"My partner and child suffered the consequences, and at one stage I truly felt they would be better off without me," she says.
"I began seeking help and found that talking to people really helped my personal demons. I noticed that we all have problems in life, and that a problem shared can be a problem halved. It was at that moment that I wanted to start my own business helping other people who have hit an all-time low."
With the help of Joanne Barber from the Landau Trust, Teri set up her own business Walk Talk Action, where she helps fellow veterans with their problems by discussing them during walks.
"As I had a passion for walking, I decided to combine this with talking to veterans and military families about their mental health along with loneliness, isolation PTSD and civilian life.
"The project is proving to be a success with national lottery funding, and recognition in the West Midlands, and I won the Armed Forces Covenant bronze award. I truly love what I do now, and feel great knowing I can help military personnel."
Also meeting the Princess was 17-year-old Charlie Doran, from Shrewsbury, whose difficulties with autism led to him getting into a few scrapes at school.
But with the help of Landau, which has its head office in Wellington, Charlie is now training for his dream job as a barber.
After starting his course in September last year he felt at home right away, and has been working as a volunteer at two barber shops in the Telford area.
"I'm loving it. If you had told me six months ago I would have done all this, and I would be meeting Princess Anne, I would never have believed you," he says.
His mother Anita adds: "He had a very bad experience at school, the staff had no idea how to manage his condition, but since he's come to Landau, the difference has been amazing.
"They give him all the help and support he needs, and if there's an issue or problem, it gets sorted."
Laundau's Patricia Wilson says his course includes working towards qualifications in maths and English, as well as learning skills that will make him more attractive to employers, such as identifying personal strengths and abilities, and exploring job opportunities to help plan his future.
Mrs Wilson says the change in Charlie's personality has been noticeable.
"When he first came here, he was quite anti-social, he had difficulty communicating with other people, particularly the staff," she says.
"It's all about taking small steps, making them believe they can do it."
The Princess also met 18-year-old Callum Smith, who has turned his life around after making some bad life choices which saw him lose his job and being asked to leave the family home.
With little choice but to move into shared accommodation, which was the scene of criminal activity and police raids, he decided to join Landau's Building Better Opportunities project, where he was introduced to employment specialist Emily Bateman.
Callum admits his problems were self-inflicted, but with Emily's support, he has been able to find work.
Emily focused on building Callum's confidence, highlighting the transferable skills he had and the areas that put him at a disadvantage, and then providing him with the appropriate training and qualifications to plug those gaps.
After exploring career options with him, she helped him produce a cv, and put him in touch with the Avara Food processing company, which had a vacancy.
Emily gave him training on interview technique, ensured he had a smart outfit for the interview, and even instructed him on what time to leave the house so that he would be on time. Since starting the new job, he has been promoted, and is now saving to move into his own home.