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.
UPDATE: Selena just canceled her performance tonight at Santa Monica Place, an outdoor mall in L.A.