Lauren Alaina sent a message out on Twitter following the Route 91 Harvest Festival shooting in Las Vegas, Nev., on Sunday night (Oct. 1). The singer performed at the festival on Saturday (Sept. 30), the day before 59 people were killed and more than 500 people were injured in the worst mass shooting in modern American history.

On social media, Alaina shared a video from her Route 91 Harvest Festival performance. She's singing her single "Doin' Fine" in front of the large crowd.

"I have been searching and searching for the words to type in this caption," Alaina writes on Twitter. "There are no words that can do this justice. Every time I close my eyes, I see this crowd. I see their smiling faces, their love for music, and their outpouring joy and happiness to be in a place that felt safe to express who they are with music. I felt truly connected with them for the 40 minutes I was on that stage, and I still feel connected to them."

Alaina, along with many of country music's brightest stars, played at the three-day Route 91 Harvest Festival before Jason Aldean's festival-closing set on Oct. 1, during which when the shooting occurred. The shooter, who has been identified as 64-year-old Stephen Paddock of Mesquite, Nev., was positioned in a hotel room on the 32nd floor of the Mandalay Bay Resort and Casino and shooting from above the crowd, gathered outside Mandalay Bay at Las Vegas Village.

"I will not let one monster steal away the beautiful and lasting impression they made on me," Alaina continues in her tweet. "I will remember them for the happiness they brought me while sharing my music with them. That's who THEY are."

Although Alaina confesses that her "heart is aching for the lives lost and the lives forever changed," she knows it's important to keep getting back up onstage "in their memory and in their honor."

"I'm going to keep getting on those stages and making memories with crowds like that Vegas crowd and I shared," Alaina adds. "Music is love. Music heals. God is love. God heals.. Let's all come together in this time."

Remembering the Route 91 Harvest Festival Shooting Victims