Selena Gomez is heartbroken that Justin Bieber has moved on.

The 22-year-old star is reportedly very upset that the 'Boyfriend' hitmaker, whom she split from last October after four years of dating, has found love again with British model Jayde Pierce and hated seeing pictures of them together on Instagram recently.

A source close to the 'Come & Get It' hitmaker told In Touch Weekly magazine: ''It drove her insane. Now, she just isn't in a good place emotionally or mentally.

''He just stopped talking to her and started having sex with Jayde.''

The brunette beauty, who sought treatment in rehab in early 2014, is allegedly trying to numb her pain by partying with her female friends, but some of her inner circle are concerned she isn't giving herself time to heal properly.

The insider said: ''She shows up for work and fulfills her obligations but then at night she's partying to excess. She might be right when she says she doesn't have a drinking problem - but she has a Justin Bieber problem that's causing her to drink.''