Selena Gomez's 'major Breakdown' Over Justin Bieber

Selena Gomez is worried her split from Justin Bieber will ruin Christmas.

The 'Come And Get It' hitmaker - who has an on/off relationship with the 20-year-old singer - is reportedly ''upset'' about his new friendship, and rumoured relationship, with Hailey Baldwin.

A source shared: ''Selena is trying very hard to pretend that she isn't upset about Justin and Hailey, but the truth is it's killing her.

''She's having a major breakdown. It's putting such a dark cloud over the holidays.''

The 22-year-old singer is believed to be suffering from ''anxiety'' about the 18-year-old model spending all her time with the 'Beauty and a Beat' hitmaker.

The source added to HollywoodLife.com: ''Selena's planning to be in Texas with her family for Christmas, but she's very worried that she won't be able to enjoy herself because she's so upset over Justin.

''She's having a lot of anxiety. Knowing that Justin is spending all his time with Hailey is eating her up.''

Recently, Selena reportedly had a very public outburst over her ex-boyfriend.

The singer - who was attending Taylor Swift's 25th birthday party on December 12th - struggled to get in the party mood.

A source at the party explained: ''She shouted, 'No one understands me! My boyfriend doesn't even understand me. [Everyone] just stared [at her].''