Justin Bieber and Selena Gomez
Ray Tamarra/Filmmagic; Splash News Online
Is there trouble in paradise for Justin Bieber
and Selena Gomez
A source tells PEOPLE that Gomez, 19, "was crying about Justin and was upset" during Ashley Tisdale
's birthday bash
But multiple photos from the fete show the "Love You Like a Love Song" singer all smiles, appearing to be in upbeat spirits. She was even photographed being twirled around by a man identified as Bieber's close pal Alfredo Flores.
TMZ reported Monday
that the young lovebirds broke up last week, but have since gotten back together.
The couple faced split rumors
last August, but quickly proved they were still an item when they sat next to each other smiling at the Teen Choice Awards.
After publicly confirming
their romance by smooching during a press conference in May 2011, their relationship has included over-the-top date nights
, a helicopter trip
and family bonding
Just a week ago, Gomez, 19, and Bieber, 18, were photographed wearing coordinating outfits
at the Katy Perry: Part of Me 3D
Neither half of the Twitter-happy pair has addressed the breakup reports.
Reps for the stars have not responded to a request for comment.
Reporting by AILI NAHAS