Why is this happening??

Ok last night i had a dream i was in the snow and two of my friends were running from me i had a shot gun and i killed them both.. then i threw the gun in the air an a bullet came out and shot me in my chest. i could feel it but it was so cold i didnt know if i was dead or not... then two more of my friend were walking an i was sittin in a lawn chair trying to catch my breath. i showed them what i did to my other friends. and thats it. its been really freaking me out cause this is not the first time i have had dreams about killing people or not trying to kill my self and it happens anyways. can you tell me what this means....?