COURTNEY COX snapped during a recent red carpet event – and now pals fear she’s on the verge of a major meltdown!

The former “Friends” beauty’s boorish behavior at the March 5 gala in Los Angeles, held in honor of Al Gore, was due to her simmering resentment over how well her ex-husband David Arquette has adjusted to single life, say sources.

When a reporter asked the 48-year-old actress if she was ex­cited to meet the former vice president, she snarled: “I will be when you stop wasting my time and let me get to my event.”

AN EYEWITNESS TOLD THE ENQUIRER: “You could tell something was really wrong with Courteney. She was throw­ing a fit right on the red carpet and was being evil to everyone who tried to talk to her.

“She made such a scene that everyone was shocked and disgusted with her. You could tell she’s become a very bitter and angry person.”

And sources say it’s all because of her ex’s success. David, 41, is expanding his celebrity nightclub chain, Bootsy Bellows, to Paris, and he’s been spotted with a num­ber of hot young women on his arm, including his younger on-again, off-again galpal Christina McLarty. Meanwhile, Courteney’s love life has flatlined since their split – and her career doesn’t seem to be going anywhere, either.

“Cougar Town,” which is in its fourth season, may face cancella­tion by TBS. And aside from a guest spot on former “Friends” co-star Matthew Perry’s NBC series “Go On,” the mom of 8-year-old Coco with David has no new projects in the works.

“David is doing great in his career and love life, but Courteney hasn’t fared so well,” added the insider.

“She should have at least tried to promote ‘Cougar Town’ or Perry’s new show at the event, but she’s clearly turned into a miserable person. Her bad behavior was all anyone could talk about that night.”