How do I learn to feel emotion?

I don't know how to have emotions. I never had any from my birth. Being human, I think of myself as a monster. I enjoy pain. I cut myself for my climax during sex. I think most of the time, I lie, even when sometimes it would have been easy just to tell the truth. I was in rehabilitation for four year. I have made love with both men and women, but it made no impact in my emotions. The books that I enjoy reading H.P. Lovecraft and Edgar Allen Poe. I go hunting every Saturday. I feel powerful. I don't enjoy the killing of the creature, but the hunt of it and to eat and drink the flesh and blood of the creature.