Last night saw a beautiful full moon.
In Ayurvedic terms the full moon is Kapha therefore in the few days prior to and including the full moon it is not unusal to have feelings of tiredness - as some of the principles of Kapha are slow, heavy, solid & stable.
Kapha is the Earth principle and is comprised of Water & Earth. Think of the effect the moon has on our oceans. Considering that the human body is anywhere between 55% - 75% water depending on age and body size, is it any wonder that the lunar cycle effects us too!