I hear voices in my head telling me to hurt anything?

Ok so basically I'm your average 14 year old boy, I hang out with my friends, play video games, play sports and spend time with my family. I grew up quite fast as my childhood ended when I was around 10. At that age I was exposed to heavy drinking, marijuana and other drugs. I'm really nice and would never hurt anything, but over the past few months I've been hearing a voice in my head telling me to inflict pain on anything that walks, not only that but it shows me what it would look like too. I've faintly seen the source of this voice. It's a tall man in a suit with a plain white face. I hear children saying he'll lead me to safety but I'm quite afraid of him. I don't know if my mind is just making this character up to give it something to look at or whatever but I'm really scared. When I don't want to hear this voice I smoke weed. I know that sounds pretty gross since I'm only 14, but like I said I was exposed to this very young. I have lots of friends so I can't be lonely. And I am quite smart, if any of you know what this means, please PLEASE tell me.