Harry Styles is feeling "unfulfilled"

A source said: "It's like he's stuck in the rock 'n' roll lifestyle.

It used to be so much fun, but he's beginning to feel unfulfilled. And the exhaustion is starting to show.

"The pressure and uncertainty are getting too much for Harry. He needs to take care of himself but he just wants to party through everything."

Things haven't been easier for departing member Zayn Malik - who quit earlier this year to have a "normal" life - as he is reportedly "freaking out" over a leaked demo he recorded.

An insider added to Star magazine: "He doesn't need this. It's freaking him out.

"He left One Direction to get away from this kind of stress, but now he's getting it from all sides. The last thing he needs is more trouble from the label and his friends fighting."

Meanwhile, Harry recently admitted he is considering a side career in fashion.

He said: "I definitely find it fun, the fun thing with clothes and everything like that is it's just complete personal opinion and so it's just whatever you want to say and you want to get across."