EXCLUSIVE: Justin Bieber's Inner Circle Worried About a Breakdown: He's 'Extremely Burnt Out'

Justin Bieber's recent questionable behavior has been increasingly worrisome to his inner circle, a source close to the 22-year-old pop star tells ET.

The "Sorry" singer was tackled to the ground during a fist fight outside of Westin Cleveland hotel after game three of the NBA Finals on Wednesday, but the incident hasn't been the only example of erratic behavior as of late. From his passionate Instagram rant about "feeling like a zoo animal" and refusing to take pictures with fans, to criticizing awards shows, and walking around barefoot in Boston, Bieber has definitely kept himself in the headlines.

"People around Justin are nervous about him and worry that he could have a breakdown," the source says. "He feels like people forget that he is a human being and needs privacy. Him writing those social posts about the 'no photos etc…,' that is him just being overwhelmed. It wasn't intended to make people think he is a snotty pop star, but it's definitely reflective of what he is going through right now. During his time off, he has been trying to be as normal as possible and trying to be super low-key about everything."

"The situation is serious and no one is taking it lightly," the source adds. "Justin is extremely burnt out and just needs a break."