Pals fear heartbroken and career damaged funnyman may be hellbent on self-destruction.

JIM CARREY was once America’s box-office champ and romancing one of the world’s most desirable women – but now his career and love life are both in the doldrums and friends fear he’s headed for a devastating breakdown.

“Jim has suffered from severe de­pression in the past, and you have to worry those fearful days are coming back again,” a close source told The ENQUIRER.

“When you talk to him, he’s not as animated as he used to be. He seems at a low point – like a ship without a rudder.”

The twice-married comic genius’ most heartbreaking problem is that he still pines for the love of his life, former “Playboy” playmate Jenny McCarthy, say insiders.

“Jim thought he and Jenny were going to be together for a lifetime,” di­vulged an insider. “He was like a father to her autistic son Evan and even hoped to have a child with her someday.

“There’s no shortage of young beauties who will throw themselves  at Jim, but he’s been searching for real love, and there’s no one to replace Jenny.”

A source says Carrey, 51, believed the bombshell blonde “was the one” after he went through a failed, sev­en-year marriage to Melissa Womer, a brief union to actress Lauren Holly and a short engagement to Oscar winner Renee Zellweger.

Ironically, while Carrey suffers, McCarthy, 40, is on top of the world. She recently became a panelist on “The View,” and insiders say she may soon be heading down the aisle with “New Kids on the Block”  star Donnie Wahlberg. Meanwhile, Carrey – who packed theaters with comedy blockbusters such as “The Mask,” “Ace Ventura,” “Dumb and Dumber,” “Liar Liar” and “Bruce Almighty” – has had only one modest hit in the past few years, “Mr. Popper’s Penguins” in 2011.

His latest film, “Kick-Ass 2,” has been a disappointment at the box office, and Carrey didn’t help the cause by declaring shortly before its release: “In all good conscience, I can’t support that level of violence.”

 THAT remark may have damaged his career as well as the movie’s box-office receipts.

“Film studios certainly don’t take kindly to an actor slamming his own movie,” said an insider. “It makes producers hesitant to work with him.”

Now, concerned sources say that Carrey’s problems could push him over the edge. He’s admitted to pre­viously struggling with depression and took the antidepressant Prozac for a long time.

“Jim has done his best to beat back feelings of depression by meditating and staying away from drugs and alcohol,” said the close source.

“His friends are very proud of him, but the joys of life have been eluding him, and seeing Jenny move on makes him ache for what they had.

“He’s in a fragile emotional state. Pals fear for his future.”