I don't know if I have the same disorder, but I definitely feel this. It's so much nicer at night. A lot of people fuck up their sleep schedule on the weekends. I keep the weekends the same as my work week and have no problems being sleepy.
But I'm considering applying for a new position at my organization which will mean I have to shift back to days. I'm not sure if the promotion is worth the headache of early mornings and the commute.