A Curious Shadowghost

As you know from before, I'm from Sweden, but this story takes place in Denmark.

I recently moved to Denmark (my fiancé is Danish) in to this really gorgeous apartment, which is located in a building from 1560's. It's a little crooked. If I let go with my feet of the floor sitting in the computer chair, it rolls a bit. Anyway, I know that there's a ghost here. First night here I was alone (my fiancé working a late night shift). I was spending my lonely hours unpacking and watching TV. I was lying on the couch, with my back turned against the dining room, when I got this feeling of being watched. I felt it so strongly I thought my fiancé had come home early and now where sneaking on me. I turned around expecting to see him standing in the doorway. What I saw, was a tall shadow leaning into the living room, and it appeared to watch me. A split second later he/she leaned back into the dining room again. I ran up and checked the dining room, but the shadow was gone. Needless to say, I ran around the whole apartment lighting every lamp I could find.

Later the same night, I took a bath, and while I was lying there, it sounded like someone walked in circles in the living room (some of the floorboards squeak a lot when you walk on them). Sure, it's a very old house, but the floorboards make a really distinct sound when trampled on.

I haven't really encountered anything else after that. I believe that the ghost here was curious of the new ones moving in, and checked if we were "ok".

So what do you guys think; was the ghost just curious? I can't think of another explanation why it would show itself only the first evening and then never again.