Ever tried to be alone in new surroundings, where you have to get used to the noises, that that particular place plus surroundings make? Or perhaps the lack of noises if you usually lives in a place with much trafic, neighbours etc.?
If I have travelled far to get to a new place, I usually just pass out as soon as my head hits the pillow. But this place is not far away (though still a little distance from my apartment) so my mind is more alert to new noises - not that I feel insecure, but the subconsience needs to get familiar with the surroundings.
Did I mention that I have company while sleeping at this place? I am catsitting again and this cute little creature has seen it as it's mission to snuggle at night.