Selma Blair talks about multiple sclerosis diagnosis

Speaking publicly for the first time about the multiple sclerosis diagnosis she revealed in October, actress Selma Blair says she cried tears of relief when she was told.

"I cried. I had tears. They weren't tears of panic," the 46-year-old star of the Netflix series "Another Life" told Robin Roberts on "Good Morning America" in an interview that aired Tuesday. "They were tears of knowing I now had to give in to a body that had loss of control. … And so when I got the diagnosis, I cried with some relief. Like, 'Oh, good, I'll be able to do something.' "

The "Hellboy" and "Cruel Intentions" star went on to explain that since the birth of her son, Arthur, 7, with then-boyfriend Jason Bleick, "I was in an MS flare-up and didn't know. And I was giving it everything to seem normal. I was self-medicating when he wasn't with me. I was drinking, I was in pain. … And I was really struggling with 'How am I going to get by in life?' And not [being] taken seriously by doctors — just, 'Single mother, you're exhausted, financial burden, blah, blah, blah.' "

Blair said she wanted her son "to feel safe, never responsible for me." He had seen her falling at odd instances, so she explained to him she had the progressive neurological disease. "And he almost cried and said, 'Will it kill you?' And I said, 'No. I mean, we never know what kills us, Arthur. But this is not the doctor telling me I'm dying. And he was like, 'Oh, OK.' "

Calling her MS highly symptomatic, she told Roberts she would drive her son a mile to school "and before I got home I'd have to pull over and take a nap. And I was ashamed and I was doing the best I could and I was a great mother, but it was killing me."

Before her diagnosis, thinking she might have Parkinson's disease, she sought advice from actor Michael J. Fox, who was diagnosed with that disorder in 1991. "He got in touch with me and we began [a] conversation. So he really helped me. Plus," she added jokingly, "I was like, 'I have Michael J. Fox's email now. I'm pretty cool! I'm cooler than I thought!' But, really, he gives me hope."

Blair, who attended Vanity Fair's traditional Academy Awards after-party Sunday in a couture dress and custom-decorated cane, wrote on Instagram Tuesday, "I pretend I am good #sorceress … Power comes in unlikely forms," she captioned a black-and-white Cass Bird photograph of her from an interview in the magazine's new issue. "Like all of us with disease. Or none at all," she concluded enigmatically.