The former WWE star – who Anzaldo found unresponsive in her Redondo Beach, California apartment a week ago – was eight months into filming a documentary called The Reconstruction of Chyna that would have culminated with her back in the ring this coming fall, Anzaldo says.
"The goal was she has to go in gets her health, she triumphs, she wins," he says. "That was going to be her Rocky ending to this amazing documentary."
Even though Chyna, real name Joan Marie Laurer, was in what Anzaldo calls "amazing shape," the emotional process of living life and in front of the lens and confronting her demons had led the 46-year-old to self-medicate with her prescriptions: "sleep aid Ambien and a form of Valium, an antianxiety pill," he says.
"Chyna died from an accidental overdose that took place over a period of about three weeks of her unintentionally and inappropriately handling two legally prescribed, prescription medications," Anzaldo says. Authorities with the L.A. County coroner's office previously told PEOPLE that investigators have come to a similar conclusion, but the coroner has deferred ruling on a cause of death pending additional investigation.
Anzaldo insists that Chyna – who once appeared on Celebrity Rehab – wasn't "out of control," and says there was no alcohol or illegal drugs at her home in the weeks leading up to her death. He believes her accidental over-medication was a coping mechanism for the issues Reconstruction had brought up.
"We were getting into the emotional aspect of her [mind, body and soul]," he tells PEOPLE. "A lot of abandonment issues. Domestic violence. She was seeing a therapist."
In addition, the WWE legend had recently rekindled a relationship with her family for the first time in nearly 30 years – a process she had started with her mother a few years prior, after her father's death. Anzaldo explains that Chyna had a falling out with her parents at a young age over typical teenage rebellion. "The next thing you know... they don't ever speak."
"The family aspect of it – It's her facing a lot of her own emotions and issues," Anzaldo says. "So it was getting a little bit intense for her and she probably was just inadvertently taking her meds a little bit inappropriately. Once we found out that was happening, we knew that there was a problem, and four days later she was gone."
Courtesy Anthony Anzaldo
Anzaldo says that he noticed Chyna's abnormal behavior and planned an intervention to help take control of the increasing substance abuse. With the help of television's Intervention – which expedited the challenging process to a mere eight days – Anzaldo was ready to get Chyna the help she needed, which included 90 days in a treatment facility. Unfortunately, it was too late.
Despite her struggles, Anzaldo says she was "never happier than she was at the end," and spent her days doing yoga and practicing the cello in preparation for an upcoming recital. Traveling the country to meet her fans also renewed her energy after five years of living overseas.
"The fans were her life, her pulse, they were her everything," Anzaldo says. "Everything to her."
Part of her travels also brought the 9th Wonder of the World back into contact with the wrestlers she once sparred with. "She was really, really surprised and excited she started going to a lot of these wrestling autograph shows and she was seeing some of her old friends and they were giving her nothing but love. Roddy Piper: nothing but love. Bret Hart: nothing but love. Stone Cold Steve Austin: nothing but love. Mick Foley: crazy love. Billy Gunn: unbelievable. Kevin Nash: nothing but love. Pete Rose."
Some of the former wrestling champions were among the first Anzaldo called when Chyna died last week. "She gave her heart and soul to everything she did and she loved the business and she was a pleasure to be around and she was a breath of fresh air," Austin said on his podcast. "And I was sorry to hear on April 20th, when I got that phone call, that she had passed away and it was indeed true."
Anzaldo says Chyna's family, while "devastated," are "grateful for the time that they were able to spend together towards the end and rekindle their relationship."
While he will handle Chyna's estate and cremation, and already donated her brain to Concussion researcher Dr. Bennet Omalu for study, Anzaldo says the star's mother has planned another way to honor her: through a special line of clothing for rescue dogs, a joint passion for the women.
"I'm sad I'm not gonna see my best friend again. Her mother's sad she's never gonna see her daughter again, but we are so grateful that she was a part of our lives," Anzaldo shares.
Anzaldo says that all fans will be welcome to a public memorial for the star, tentatively planned for June 9 in Los Angeles.