People.com: How Britney Spears Is Doing Post-Split

A breakup can really ruin your day. But if you are Britney Spears, the show must go on. 

Hours after the news broke that she had split from boyfriend David Lucado, the singer, 32, hit the stage at Planet Hollywood in Las Vegas. 

"She looked amazing and seemed to be doing great," a source tells PEOPLE. 

Adds another source: "She is upset, but she's focusing on her show right now. She's moving on." 

Before she performed, Spears posted an Instagram video (featuring some NSFW language) addressing her newfound singledom. 

"If you ever have a really, really sh---y day," she says, "find somebody with shoes with hearts on them." She then pans to a friend's (really cool) heart-adorned sneakers. "Made my day," Spears says with a grin. 

All had been fine between the couple until Spears's father, Jamie, informed her of the existence of a video proving Lucado was cheating, PEOPLE has learned. (TMZ was the first to report the news.) 

Spears broke up with Lucado immediately. "There is no way she would ever take [Lucado] back," an insider says. "It's over for good." 

Source: People.Com