The 18-year-old 'Baby' hitmaker is apparently keen to win Gomez, 20, back, reported Hollywood Life.
"Justin is devastated and pathetic right now. He is calling her 100 times a day and she is not picking up. Selena and Justin flew to Mexico for New Year's Eve, but had a blow-out argument on December 30 and broke up.
"Selena left Mexico that same day and Justin left for LA on December 31. They have not seen each other since," a source said.
Previous reports claimed Bieber and Gomez mutually decided to part as things aren't working between them.
"Justin and Selena were together for a long time. They love each other and will always care about each other, but it just isn't working between them," a source said.
"So they ended it. Selena is Justin's first love and he is still young enough that he desperately tries to make it work. But Selena is mature enough to just know when to end it and be realistic that it isn't working," the source added.
