"Her friends and family are stunned. Annabelle had a lot of hard times in her life," a source tells PEOPLE

By Alexia Fernández
July 16, 2018 08:06 PM

Annabelle Neilson‘s death at the age of 49 has left those who knew her shaken.

“Her friends and family are stunned,” a source tells PEOPLE about the Ladies of London star.

The source says Neilson endured plenty of “hard times” in her life, most notably the 2010 suicide of her best friend, designer Alexander McQueen. “She was rocked by his death,” says the source.

She also had a horse riding accident five years ago that left her in agony. “Coping with the pain was horrific,” says the source.

Ultimately, says the source, “she had a lot of private pain that she kept from others.”

The Bravo personality and British aristocrat’s death was confirmed by PEOPLE on Monday. Details surrounding her death are not available at this time.

Prior to her death, the former model worked with supermodels such as Kate Moss and Naomi Campbell and was exceptionally close to fashion designer Alexander McQueen before his death.

McQueen’s passing especially left a lasting impact on the TV reality star, who was the last person to see the designer alive.

"Buttercup Bill" - UK Premiere - VIP Arrivals
Annabelle Neilson
| Credit: David M. Benett/Dave Benett/WireImage

“He was my brother, my boyfriend, my soulmate,” she told the Daily Mail in 2015. “Most of the time people called me Mrs. McQueen. Quite often we were sharing a bed.”

“The truth is I was happier with Lee than with anyone else,” Neilson added. “He asked me to marry him towards the end and I said no. I wish now that I had said yes.”

Neilson was open about her struggle with heroin addiction in the past. She told the Daily Mail in 2015 that her addiction began when she was attacked by a man at the age of 16.

“The attack lasted for two hours. I was tied to a tree and continually beaten. I looked like the elephant girl by the end of it,” she told the outlet.

Annabelle Neilson life in photosCredit: Annabelle Neilson/Instagram
Annabelle Neilson
| Credit: Annabelle Neilson/Instagram

“I managed to escape with my life but I needed reconstructive surgery because my face was so disfigured,” Neilson revealed. “After that, I fell into a serious depression and became a heroin addict because it provided an escape bubble and was the only way I could cope.”

She was later able to remain sober.

In 2013, Neilson, an avid horse racer, was thrown off the saddle. After 12 weeks, she was told by doctors she could never ride again — and suffered chronic pain following the incident.

“The truth is I was happiest when I was training,” she told the Daily Mail. “I love the connection with these great animals and, although I grew up riding, racing is completely different.”