The X Factor judge was photographed at LAX wearing a long black skirt with an ivory sheer blouse and round black shades.
Understandably, Demi didn't seem especially cheery, but she reassured fans on Twitter that, "Today, I feel stronger..."
"Even though these past few days have been difficult, I learned that I have so much support and love from my fans and that makes me so happy," she tweeted.
Something else that brought some joy to the star was the Supreme Court's decision to shoot down Prop 8 and the Defense of Marriage Act (or DOMA).
News of Patrick Lovato's death went public over the weekend. Details regarding the circumstances of Patrick's death haven't been released, but he reportedly was battling cancer for the last couple of years.
Demi broke her silence regarding the tragedy on Monday.
"I feel so humbled to have had so much support from my fans, friends, family and complete strangers.. ," she tweeted. "God bless you all, thank you so much."
The following day, Lovato posted throwback photos of herself with her father and wrote, "RIP Daddy.. I love you.. Love, Your little partner ❤"
Demi, who had been estranged from her father, told the New York Daily News in 2009 that she hadn't talked to her father since 2007.
"The last time I talked to him was two years ago," Demi said. "You try to have faith in somebody, even when you're the last person that believes in him. But when somebody lets you down after you've been the only one there for them, and so many times, you don't know what else to do. I had to cut off all connection. It was hurting me too much."
Demi also discussed her relationship with her father in her song "For the Love of a Daughter."