I have been dead to the world since giving up two weeks ago. I think it is 100% normal though the reasons dictated vary, I am sure they are all true to a degree.
I have been drinking lots of green tea, keeping coffee (love strong black coffee) down to 2-3 cups a day since I guess it will only make it worse, lots of water, vitamin supplement every other day and eating well.
It seems to be getting easier - I know I definitely still feel better for not waking up after the night before...