Teleported to Another World. Why am I a Vampire

Life in the 21th century  isn′t soo bad. We have videogames, anime, movies... and I′m just an ordinary guy, living an ordinary life, playing games all day until the time to get a job finally comes and my parents kick me out of my bedroom. However... it seems I was kicked a bit earlier... and these fangs in my mouth... doesn′t help explain what happened.