March 6 (UPI) -- Chrissy Teigen is opening up for the first time about her battle with postpartum depression.
"I had everything I needed to be happy. And yet, for much of the last year, I felt unhappy. What basically everyone around me -- but me -- knew up until December was this: I have postpartum depression," Teigen shared.
"I went back to work on Lip Sync Battle in August," she recalled. "Getting out of bed to get to set on time was painful. My lower back throbbed; my shoulders -- even my wrists -- hurt. I didn't have an appetite ... I couldn't figure out why I was so unhappy."
"When I wasn't in the studio, I never left the house. I mean, never. Not even a tiptoe outside," the star confessed. "There was a lot of spontaneous crying."
The Sports Illustrated model was diagnosed with postpartum depression and anxiety during a visit to her doctor in December. She improved after starting an antidepressant, although she still sometimes has "bad days."
"I'm speaking up now because I want people to know it can happen to anybody and I don't want people who have it to feel embarrassed or to feel alone," the star said. "One thing I do know is that -- for me -- just merely being open about it helps."
"I am a much different human than I was even just in December," she added. "I love John and Luna more than I can imagine loving anything, and John and I still hope to give Luna a few siblings. Postpartum hasn't changed that."
Teigen, who conceived via in vitro fertilization, gave birth to Luna on April 14. She responded to critics in a series of tweets in January after announcing plans to welcome a baby boy via IVF in the future.