Entertainment Music Demi Lovato's Sister Madison Celebrates Singer's Birthday with Emotional Tribute on Instagram "Today could have been one of the worst days of my life," wrote De La Garza while thanking Lovato's team and fans for their support By Melody Chiu Melody Chiu Instagram Twitter Melody Chiu is a Senior Editor for PEOPLE. She has been with the brand since 2009, editing, writing and reporting across all entertainment verticals. She oversees PEOPLE's music and events coverage and has written cover stories on Taylor Swift, Selena Gomez, Melissa McCarthy, Blake Shelton and Sandra Oh. The Los Angeles native graduated from the University of Southern California and has appeared on Extra!, The Talk, Access Hollywood and Good Morning America. People Editorial Guidelines Published on August 20, 2018 03:05 PM Share Tweet Pin Email Photo: Alberto E. Rodriguez/Getty Images Demi Lovato’s younger sister Madison De La Garza broke her silence about the star’s relapse and overdose on a very special day: the singer’s 26th birthday. “Today could have been one of the worst days of my life, but instead i get to spend it thanking God, the incredible doctors, demi’s team, and everyone across the world who offered their support — without all of these people i wouldn’t have my big sister anymore,” the 16-year-old actress wrote Monday in a heartfelt tribute to Lovato. “I’ve been thinking about how i wish that everyone could see the silly little things that she does, like how her nostrils move when she says certain words and when she brushes my hair behind my ear when i’m trying to sleep, because those are the things i’m so thankful for today,” she continued on Instagram while sharing a childhood photo of herself and Lovato. “They seem so small, but those little things make up my sister — not a singer, not a celebrity, and definitely not what she’s been described as in the media — she’s a daughter, a friend, and my big sister… and i am so, so thankful that i can tell her happy birthday,” De La Garza concluded. Sources previously told PEOPLE De La Garza rushed to her big sister’s side after her shocking overdose last month and was one of her biggest supports through her latest setback. In 2011, the “Confident” singer also agreed to cut out drugs and alcohol from her life after she was issued an ultimatum by their mother Dianna De La Garza: Get clean, or she would cut off contact with Madison. “That was a very heartbreaking time in my life because we basically sat down with Demi and said to her, as much as it hurt me, ‘You have to get serious about getting help and getting sober because you have a little sister, and I can’t allow her to be around you if this is how it’s going to be,’” De La Garza previously told PEOPLE. Everything We Know About Demi Lovato’s Overdose — and What’s Next “That was the defining moment for her. That’s when she took her phone, smashed it and put it in a glass of water, as a sign that she was ready to commit,” Dianna wrote in her 2018 memoir Falling with Wings. “Thank you for all your love and prayers… I am truly blessed. #thankful #happybirthdaydemi,” Dianna wrote on Twitter and Instagram Monday, sharing her daughter’s post. RELATED VIDEO: Demi Lovato Breaks Silence After Overdose and Hospitalization: ‘I Will Keep Fighting’ After being released from the hospital on Aug. 4, Lovato has been undergoing in-patient treatment and thanked her fans on social media for their support in an emotional statement. “She’s in the midst of recovery,” a source close to Lovato previously told PEOPLE. “It’s going to be a long road, and Demi knows that. Emotionally, it hasn’t been easy, but she’s doing okay.”