By Paul Chi and Liza Hamm
Updated September 21, 2009 12:00 PM

Back in 2004, Paige Hemmis, the bubbly carpenter with the signature pink tool belt on Extreme Makeover: Home Edition, nodded off in the middle of renovating a house in Penngrove, Calif. It wasn’t the first time she had fallen down on the job. “I’d pass out a lot on the set,” she says. “And I was so sleep-deprived that behind the wheel I was worse than a drunk driver.”

But her lethargy wasn’t caused by pulling all-nighters for her ABC show or clubbing until dawn. Hemmis, now 37, was suffering from severe depression, which caused inexplicable crying fits, insomnia and binge eating (that same year, she gained 25 lbs. in just two months). “It’s like someone turned the lights off and I was going through the motions in the dark,” she says. “Give me a broken sink and I can fix it, but I couldn’t fix myself. I felt powerless.”

Ironically, Hemmis didn’t equate her symptoms with depression, even though both her mom, Karel Huff, 62, and grandmother Joyce Thomson, 87, had struggled with the disease (they had never discussed their symptoms with her in detail). Also, “I had this preconceived notion that if you were depressed, you were ready to commit suicide,” she says. “I didn’t feel suicidal.”

No, just lethargic and numb. “Nothing gave me pleasure,” she recalls. “I would withdraw, because going out and putting on a fake smile was exhausting.” So while filming Extreme Makeover, Hemmis turned down most social invitations and holed up in her hotel room eating junk food. “I was constantly telling myself to snap out of it,” she says. “I knew I should be eating better, but I didn’t have the strength to make a difference.”

To make matters worse, her marriage to Russ Hemmis was also falling apart (they divorced in 2005), though she says their problems started before her depression. Still, after they split, “I was very lonely and depressed about dating,” says Hemmis, who is now in a relationship with a man she declines to identify.

Later, in 2004, she went to her doctor complaining of insomnia and ended up being diagnosed with a major depressive disorder. She was stunned. “You’ve got the wrong person,” she thought. “I’m ‘smiley girl!'” But her family and friends had noticed a personality change. “She wasn’t the same Paige,” says Huff. “We were very close and suddenly we weren’t. I attributed it to the fact that she was working so hard.”

Ultimately Hemmis dealt with her depression by attending biweekly therapy sessions for six months and taking antidepressants until August 2008. Now, she says, it’s under control, but a few key adjustments to her daily routine—like getting six hours of sleep a night and taking long walks, which helped her shed all the weight she gained—help her with minor ups and downs. “I hate to exercise, but I love walking. That helped clear my head,” she says. So does a little pet therapy: “I bring my cat Mercury on the road. She’s my little piece of home and makes me feel not so lonely.”

Talking openly about her depression has helped too. Hemmis was initially ashamed to discuss it, especially because her Extreme Makeover work introduces her to families struggling through incredibly hard times. “Their stories are heart-wrenching,” she says. “I felt guilty for feeling that my life was miserable.” At first she only confided in a few close pals. But when one of them later confessed that Hemmis’s story inspired her to seek help for her own bout with depression, the Wisconsin-born designer knew she had found her next project.

“If I can help someone think it’s not so scary to talk about, it’s worth it,” says Hemmis, who has joined the Blueprint for Hope campaign to raise awareness about depression. “It’s a part of who I am, and I am fine with that. I feel better than ever.”