To me, a lot of dreams just seem to be parts of our life that string together. I think that this dream is trying to say that you would feel empty without your friends, and that maybe you feel that they are slipping away from you(because you were looking for her). The fact that you knew you had killed them might suggest that you feel guilty about something or would feel guilty if you lost their friendship.
Also remember that I'm not an expert by any means, so take my interpretations or throw them out the window, it's your dream and it's up to you