Selena Gomez Rushed to Hospital

"Selena Gomez was rushed to the hospital last night, just after she appeared on "The Tonight Show" -- TMZ has learned. Sources tell us ... Gomez was feeling horrible during and after the show, complaining of nausea and a severe headache. 

She was taken to a Los Angeles area hospital and is still there, undergoing tests.

We're told the exact cause of her illness is not yet known." (TMZ)