The reality TV personality suspended filming of her MTV show Crazy In Love as she is "just a little down", according to her spokesperson.
A source told The Sun: "She’s been locked away in her bedroom for days just staring at the wall - severely emotional and depressed. Everything she was reading in the press has built up."
Mother-of-three Katona has visited the rehab clinic three times before - once after her split from Westlife singer Brian McFadden and on a second occasion when she battled alcohol addiction in 2005.
Katona last visited the centre when she was the victim of an armed raid at her home in Wilmslow, Cheshire.
A spokesperson for the former Atomic Kitten star said: "Kerry has not suffered a nervous breakdown. She suffers from bipolar disorder and is just feeling a little down."
The I'm A Celebrity... winner is expecting her second child with husband Mark Croft in May.