Selena Gomez Performs in Santa Monica After Hospitalization

At her first appearance since falling ill Thursday night, Selena Gomez proved she was on the mend after a brief hospital stay.

"I do feel better," she told the crowd at Santa Monica Place on Monday, where she performed with her band, The Scene.

Gomez, 18, explained to E! Online that she was "very malnourished" when she appeared on "The Tonight Show" Thursday.

She was subsequently hospitalized after reportedly complaining of nausea and a severe headache.

"I was dehydrated," the starlet recalled, "and I was very low on iron."