A dream that features horror, or where you are “in” a horror movie, must be analyzed for the various parts in the dream.
It is not necessarily a bad omen - try to break down what happened in your dream, and look up the meanings of each symbol or situation.
[1]This element in a dream must be correlated with the features that figured in its cause in order to determine its meaning, therefore it need not, necessarily, be seen as an unfortunate omen.
[2]