JB has had enough!

Justin Bieber has been exhibiting some pretty strange behavior in recent months, and his friends are allegedly worried he's having a breakdown due to living his life in such a spotlight.

"People around Justin are nervous about him and worry that he could have a breakdown. 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," a source dished to ET.

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

These reports come on the heels of his fist fight in Cleveland, and now we're learning the real reason for that brawl. Apparently The Biebs called some 6"5 guy a "motherf**ker" when he asked for an autograph and photo.

Everyone needs to leave Bieber alone! Like he says, he's not a zoo animal!