Shannen Doherty is opening up about how her breast cancer has returned.
The 48-year-old 90210 star was originally diagnosed with breast cancer in February 2015, but after the cancer went into remission, Doherty is revealing that it has come back as Stage 4.
The actress has been living with the diagnosis privately for almost a year now, but due to a court case with her insurance company, which details her health issues, she chose to come forward with the news herself to control the narrative surrounding her cancer.
"I don't think that I've processed it. It's a bitter pill to swallow in a lot of ways," Doherty told Good Morning America's Amy Robach during a Tuesday interview. "I have definite days where I say, 'Why me?' And then I have days where I say, 'Why not me? Who else? Who else besides me deserves this?' None of us do."
Doherty was living with this news while preparing to film the reboot of her teen drama, BH90210, when she learned her Beverly Hills, 90210 co-star and longtime friend, Luke Perry, had died of a stroke. When she heard of his death, her first thought was, "Why wasn't it me?"
"It was so weird for me to be diagnosed and then somebody who was seemingly healthy to go first," she said of Perry. "It was really shocking and the least I could do to honor him was do that show. I still haven't done enough."
She noted that she only told co-star Brian Austin Green about her diagnosis and he helped her get through filming and the loss of Perry.
"I had moments of great anxiety where I thought, 'I can't do this,' and Brian was the one person of that group of people that knew," she said. "I told [him] pretty quickly. Prior to shooting he would always call me and say, 'Listen, whatever happens, I have your back.'"
Doherty admits to being "petrified" and "pretty scared" of the health battle ahead of her. But she wanted to show that she could still work while battling Stage 4 cancer, adding, "I want to make an impact."
When she decided to join BH90210 show, Doherty spoke with ET about why it was important for her to do so after the death of Perry. Check out our exclusive interview with the brave actress: