back to the night owl?

what is wrong with my body timing?
since i got the privilege in the new project, i can wake up very late, around 8.30 and get back home very early....before 7pm.
but why am i feeling sooo tired in the morning, feeling sleepy and need more sleep....in the meanwhile....dun feel sleepy at all at night time.
am i being a nite owl again like a few years ago? sleep in early morning and wake up at lunch time?