JIM CARREY, long prone to bouts of depression, has come down with a major case of the blues after his ex-girlfriend JENNY MCCARTHY found love again and moved in with a super-buff former fitness model.

Now pals fear the funnyman’s downward spiral may prompt a return of the condition that once forced him into treatment for mental health problems.

“Jim isn’t himself these days – and he hasn’t been ever since he and Jenny split,” a close friend told The ENQUIRER.

“But finding out she has already moved in with a guy has just sent him reeling.”

In a painful split, Jim, 48, and Jenny, 37, broke up in April after nearly five years together.

The popular “Playboy” beauty recently revealed she’s fallen for 35-year-old Las Vegas hunk Jason Toohey.

A devastated Jim has been acting strangely, say sources — and he has posted weird messages on Twitter recently. Not long after splitting with Jenny, he Tweeted the word “boing” 40 times. Then he attacked Tiger Woods’ wife in another post, claiming she must have known about her husband’s affairs.

“That was the manic Jim acting out,” says the friend. “He isn’t happy.”

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