I wake up during the night, too. I think it's because my Zanaflex wears off, and my muscles stiffen.
I try not to nap during the day, because I remember my mom telling me before the babies were born, "if they nap a lot during the day, they'll be up all night."
So I force myself to stay awake, only sitting and resting when I become weak from weariness.
Kitty, try to stay awake more during the day...it might reset your internal clock...