You know, Anna, I felt exactly the same way as you yesterday, second week in and all if a sudden you get a reality check, maybe it's stopped being quite so exciting?! But I got out some skinny clothes to motivate me, and went to Costa for a bucketful of black coffee! Had to go food shopping which did not help, so sent Boyf off round the aisles with a list while I went and put a lot of effort into choosing new bubble bath and a nail varnish.
Hope today is better for you. I for one am looking forward to working nights all weekend just for the distraction (and I usually HATE weekend night shifts!!!)
good luck