Justin Bieber Feels Like He's "Carrying the Weight of the World on His Shoulders," Says Source

Pop star, 22, recently upset fans when he said he felt like a "zoo animal'" and would no longer be taking photos

Justin Bieber's life is far from typical, but at the end of the day, he's still just another 22-year-old guy doing his best to figure out this whole adulthood thing.

Back in March, Justin announced the cancellation of all meet-and-greets on his Purpose World Tour, and just yesterday, he told fans he would no longer take pictures with them because "I feel like a zoo animal, and I wanna be able to keep my sanity."

The Biebs acknowledged "people will be disappointed," but it's important for him to pull back in order "to stay in the healthy mindset." Justin "feels a lot of pressure on him from the world," a source tells E! News, "and all the attention really stresses him out."

"Then there are the concert reviews," adds a source. "They haven't been good, and it's been weighing heavily on him."

He's also "struggling with the fact he can't do things normal people can do," adds a source. "But it takes it to the extreme in terms of his reaction, which is why he issues these dramatic statements."

A source tells E! News Justin is "feeling like he is carrying the weight of the world on his shoulders," so it's understandable how he would need a little space.

Last night, after fans responded unfavorably to Justin's announcement that he would no longer be taking photos with them in public, he explained his decision further. "Years ago it was impossible to even take a picture at anytime not everyone was accessible to a camera now everyone has a camera phone and Now it's just a different thing," he wrote. "If you think setting boundaries is being a douche I'm the biggest douche around but I think it's smart and will be the only way I last."

"I wanna enjoy life and not be a slave to the world and their demands of what they think I need to do!!" he continued. "I love the fact that I am able to make people happy but cmon if you truly were in my position you would understand how tiring it is (boo hoo Justin get over it) I'm going to keep making decisions I feel are fit for my growth and no human being will make me feel bad for it."

—Reporting by Beth Sobol