EXCLUSIVE

Kim Richards just broke from stress when she was arrested early Thursday at the swanky Beverly Hills Hotel.

Sources very close to Kim as well as sources connected with "Real Housewives of Beverly Hills" tell TMZ, she was unable to cope with some pretty terrible things going on in her life.

-- Her ex-husband Monty, who still lives with her, is dying of stage 4 cancer.

-- Her son Chad was released from UCLA Medical Center hours before the meltdown.

-- She's under financial stress. Contrary to reports, she's getting no money for child support.

-- Kim is trying to plan her daughter Brooke's official wedding.

But the real trigger ... we're told earlier in the evening, Kim went to Brooke's house, where they watched the 3-part reunion. Kim had put it off because it was too upsetting, but she had to binge watch in order to fulfill her obligation to blog about the shows. And reliving what went down crushed her.

We're told Kim has been deeply upset over Lisa Vanderpump and Lisa Rinna. Kim believes Vanderpump had intentionally driven a wedge between her and sister Kyle. On the show, Vanderpump urged them to reconcile, but Kim claims off camera Vanderpump told Kyle that Kim didn't want her at Brooke's wedding ... which infuriated Kyle and deeply hurt Kim.

Our sources say the cumulative stress was too much for Kim to bear. We're told she left Brooke's house and ended up alone at the Polo Lounge at the Bev Hills Hotel. It's unclear what if anything she drank there, but Kim has told friends a group of people at a table invited her to sit at around 1:30 AM, but the maitre d' wasn't having it and ordered Kim out.