Strange Nightmare Needs Interperting

I think that maybe, from perspective, watching yourself getting murdered means you are aware of the situation that is harming you even though it might be a very harmful thing that you have or are dealing with right now. Keep an eye out for people around you that may seem like they aren't really addressing a severe issue with seriousness. The person laughing while you are getting murdered might indicate that indeed there will be a situation in life that you are really trying to get past, where you felt you lost your mind (therefore, maybe that is why your head was being chopped off) and then while this happens there might be people you know you aren't very kind hearted towards the situation in which you are dealing with. This could be a warning or simply a release of stress and anxiety about life situations dealing with deception.

I agree with BornAnArtist, this is clearly a warning dream about that person, who seems to be plotting against you, maybe planning to use you as a scapegoat for her own acts through slander, or cause a serious issue between you and someone, or steal something vital from you- your job or your partner. I would stay away from her if I were you.

maybe it means that the person you think is your friend is really a close enemy. ever heard of the saying, keep your friends close, and your enemies closer? maybe secretly your friend is involved in something that is against your beliefs and may be trying to infiltrate your beliefs with theirs.

If this relates to your life, it could mean you fear the loss of a job or something important (your head chopped off), your seeing this happening to you (watching yourself) and you feel alone(a good friend laughing).