Dakota, who was promoting her new film Black Mass, said she worried about her future in Hollywood at the age of 26.
But she suggested matters were much worse for Working Girl star Melanie Griffith, 58, and Hitchcock muse Tippi Hedren, 85. "Why isn't my mother in the movies? She's an extraordinary actress," the actress said.
"Why isn't my grandmother in the movies? This industry is brutal. No matter how tough you are, sometimes there's the feeling of not being wanted. It's absurd and cut-throat.
Whenever I have downtime, I'm unsure that I will ever work again. I don't know what it is, but it's a definite thing that happens to me," she said.
Dakota Johnson said she remained proud of her work in Fifty Shades of Grey, the erotic romance that was panned by critics.
"I'm proud of Fifty Shades of Grey. I don't need to distance myself from that. The more work I do, the more the general public sees the different things I can do. Do I think it opened doors? Yeah. More people know my name."