Rihanna suffering breakdown?

Rihanna is on a downward spiral insiders fear.

Sources say the What’s My Name? hitmaker, 23, is running on empty due to her recent out-of-control partying.

“She’s been smoking so much that it has been hurting her voice,” a pal told In Touch Weekly.

“And she has to work out extra because of the amount of alcohol she drinks. They’ve asked her to calm down, but if she doesn’t, her record label may soon begin making threats.”

Sources recently revealed how Rihanna has been ordered by doctors to curb her partying lifestyle.

“Rihanna is running on empty but she’s still been going out drinking and living it up,” a source said.

“She doesn’t have any down time where she can completely relax. She spends most of her time in the studio, on stage or in clubs. Doctors are worried she’s overdoing it.

“She needs to take some time off. Otherwise she’ll be vulnerable to more illness.”