Justin Bieber was ''unhappy'' with his life.

The 'What Do You Mean' hitmaker admits there have been times where he felt as though he had ''forgotten'' who he really was.

He shared: ''I went through a point of doing it for myself and doing everything in the industry for myself and I was unhappy because being able to do stuff for others is the biggest gift of all.

''I was robbing myself by not enjoying the moments where I should've been enjoying them and doing stuff for other people. I forgot what I was about, what my mom raised me to be. I veered off, and I got tainted.''

And the 21-year-old singer also admits people have ''taken advantage'' of him in the past.

He added to Complex magazine: ''I came into the music industry at 13. I was trying to trust people and they'd break my heart at 15. You have your perceptions of people. There are awesome people who are the lovely, amazing, joyful kind. But I only saw people who are s****y and were taking advantage of me.

''When you have that perspective, the way you act changes. I was basically like, F**k everybody. Then I started doing my own thing. I got into a little bit of trouble -nothing that other 20-year-olds don't get into - just rebelling a little bit. Now, being 21, I'm coming into my own and around some pretty cool people who are not afraid to tell me what's real.''