Christina Applegate gave birth to daughter Sadie Grace last month, an experience she says has "changed her life." The actress shows off her baby girl on the cover of PEOPLE this week.

"I felt my heart literally open up for the first time and like wrap itself around her. It was profound," Applegate, 39, said, adding she's "more in love with her every minute of the day."

After a tumultuous few years battling -- and beating -- breast cancer, the actress now understands there's so much in life to be thankful for.

"I've had to talk about that word [cancer] more than I've ever had to talk about a word in my life," she said. "After a while you're like, 'There's got to be something else to me.'"