What if you were a newly bitten vampire?
What if you had to kill somebody and drink their blood?
What if you refused to kill and would be killed in response?
Well, I was a vampire and I had to kill somebody and drink their blood or I would have been killed myself. I walked in darkness through shadows, talked in whispers and spy from afar both humans and vampires.
To dream that you are a vampire signifies that you are sucking in the life energy of others for your own selfish benefit.