I dreamt I brutally murdered someone...what does it mean?

I was having a nightmare that my mom, my stepdad and myself were running away from 4 gangster guys. We hid in the gvines but they found us, and then proceeded to threaten us. They told my mom to shoot my stepdad, and they gave her a gun (with a silencer, I specifically remember that) and she shot him in the head. They told her to kill me next, but she hesitated, and then suddenly other people hiding in the gvines jumped on the guys and told us to kill them. I bashed a guy's head in with a nail file (?) and chunks of his brain came out on it. Why am I having such gory nightmares?! Help!