Weird sound coming from wall or maybe ceiling?

[Tuline Ma]

Hi guys, every night I hear a hard thump. It’ll be a single thump every now and then throughout the night. Sometimes I’ll hear it just once and that’s it, other times I’ll hear it twice and other times more. It sounds as if someone drops a book or something heavy

I really can’t locate the sound exactly but it doesn’t sound like it’s coming from above my head when I’m in my room. Maybe if I was in a different room I could locate it better. 

Oh and I’ve also noticed my cat would wake up from her sleep and stare at the door of my bedroom and then jump of the bed and just continues staring at it anxiously? She’s done that at least four times but has stopped now, I guess she got used to it. Two of the times she did this, I couldn’t hear anything 

Thoughts?