Unexplainable thumping?

Okay so, I was in my room doing some creative writing when my little sister knocks on my door and asks if I’d stop “making those thumping sounds”
I wasn’t doing anything but writing on my phone. I told her this and she became scared and then said “I’m really scared because in my room there’s a lot of thumping and things sound like they’re getting knocked over.”
So I said she could sleep in my room. But as I go to get the sheet from the linen closet, I hear a loud thump behind me. Kind of like when your knuckles accidentally smack against the wall. I asked if she did that and she said “No!” and became frightened once more.

We’re both in my room, she’s asleep now, and as i’m writing this I’m occasionally hearing thumping coming from her room. I’d like to know, whats a good explanation to the sounds that are not paranormal.