The 49-year-old star left her role in Magic Mike's third film as theatrical and is believed to be struggling amid her split from 52-year-old Ol Parker, with whom she has three children.
She flew from London to the US last week and her team is hoping to get her support amid fears she is in a "bad place".
The "stressed" Thandiway is said to have fired his UK agent after three decades.
Last week The Sun reported how she got into a row with her co-star Channing Tatum on the set of Magic Mike's Last Dance.
She was replaced in an unspecified role by 55-year-old Salma Hayek.
Warner Bros. later said that they had made the "difficult decision to walk away from production to deal with family matters."
A source told PageSix in the US, "Thandiwe was acting strange on the set, she has been stifled a lot."
He said her behavior caused "so much disruption, it became clear she couldn't play the role. There's a lot going on in her personal life."
“She and her husband are separated. She seemed so stressed out, she even brought her two pet rabbits to her hotel for emotional support.
"She fired her UK agent of three decades, and then her US agent, Gabby Morgerman, flew to Los Angeles to try to calm things down."
Thandiwe married Ol, best known for directing 2018's Mamma Mia! Here We Go Again, in 1998.
They have 21-year-old daughters Ripley and 17-year-old Niko and eight-year-old son Booker Zombe.
The couple has not been seen together in public since vacationing in Ibiza in mid-2020.
When contacted for comment, representatives for Thandiway did not respond.
Speaking in 2008 about the secret to a good marriage, she said: "You always have to take the time to be together, trust your instincts and force each other to talk. It's communication and It's about working together in tough times."
The Mission: Impossible 2 and Line of Duty star was appointed an OBE in the 2019 New Year's Honors for his services to film and charity.
Last year she said that she was revamping her professional name as Thandive, known as Thandi for 30 years due to misspellings in her debut film.