The Bajan star has been ordered to avoid clubs and other drinking holes — or risk making herself seriously ill.
The rundown singer was forced to cancel a gig in Sweden over the weekend after suffering a bout of flu.
As well as getting on the tequila shots every other night on tour, she's been staying up until 8am recording her new album after each show.
A source said: "Rihanna is running on empty but she's still been going out drinking and living it up.
"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."
Rihanna's mates have been checking in to see if she's OK.
Rapper Jay-Z and US X Factor judge LA Reid have both sent flowers and wished her a speedy recovery. Hopefully she'll take doctors' advice and spend more time in front of the telly over the next couple of weeks.
Her UK fans will want her re-energised before her Loud tour resumes at London's O2 Arena on November 13.
She's got 15 British dates to play before the tour ends at Christmas.
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