The action described sounds like a sacrificial rite, specifically a priest performing a ritual blood sacrifice. Such rituals took place in a number of ancient religions, from the Jewish Yahwist tradition to the Mayan human sacrifices. Other details of the dream may provide more information as to its specific meaning.
This dream suggests your need to get rid of old habits that have defined you.
The taste of blood in this dream is a powerful metaphor representing your feelings of guilt and responsibility.
In this dream, the blood could represent your health. Carrying the blood in the bag might suggest that you are taking chances with your health.
It mean you had a bad dream.
It could mean something in the real world knowing you need to finally step away from that something.
Dreams about blood can have many different meanings depending on other elements in the dream. Similarly, dreaming of one's niece could mean many different things depending on what the niece is doing in the dream. A basic principle in understanding dreams is that the dream is about the dreamer, not about other persons that appear in the dream. So the blood and the niece in this dream reflect something about the dreamer's feelings, memories or experiences.
The dream illustrates conflicted feelings of wanting both to get rid of something nasty at the same time one hesitates to get rid of it completely.
You will lose something minor/major. (an object, person, friend or etc...)
it means you are having a nightmare and nothing else.
This dream suggests feeling as if someone is trying to cast blame on the dreamer. It reflects the expression of having "blood on one's hands."
you watch too many movies
This dream might have two opposite meanings. If someone is throwing stones AT you, it suggests that you have made someone angry. Note that the "someone" could be a part of yourself, in the sense that on one hand you did what you felt needed to be done, and yet you are angry at yourself for doing it. But if the dream is of someone throwing stones TO you, that suggests that someone is trying to help you by providing basic building materials from which you can build something new and strong. Again, the "someone" can be an aspect of yourself.