Hi,
Okay well I'm hazarding a guess that you are breast feeding your little one. If so then they do tend to sleep less between feeds than bottle fed babies. Also because your little one is sleeping so much during the day he needs to top up his food during the night. If at all possible what you need to try and do is get him to feed more during the day from you(not easy I know). If this doesn't work then try waking him half an hour earlier each day so that his little body clock readjusts gradually. If you can possibly sleep when he does then do; catnaps during the day can work wonders! Also when you feed him at night I would keep the lights as low as possible and keep interaction to a minimum so that he begins to recognise that there is a difference between night and day. Baby massage is also an excellent way of relaxing your baby after their night time bath and this would be a great time to incorporate Reiki too :)
Take heart the newborn stage and the insane tiredness that you are feeling doesn't last forever :)
Gentle Blessings
Helen