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.