Poltergeist in a rented apartment: object movement and a sense of presence

My mom and I moved into a new apartment 3 weeks ago. We rent it. And as an apartment it's good, a big cool studio, but some weird shit happens in it. All these 3 weeks I've started sleeping badly, I take very long to fall asleep, because I'm sure I'm not alone in the room. The worst part is that Mom works evenings and nights and comes home around four in the morning and goes to bed, so I have to be alone. My little couch stands with its back to the window with a wide windowsill on which all sorts of things lie and there's a big pot with an overgrown houseplant, idk what it's called, thick stems at the bottom with hard large leaves growing above. Because I feel that I'm not alone in the apartment, I lie down with my back to that windowsill, so that opening my eyes at any moment I can immediately see the whole room. And when I lie like that I just know that at that moment something is looking at my back from that windowsill, but I'm afraid to turn around and see what exactly is sitting there. And then that something starts moving the branches of that plant. I noticed this a long time ago, but when I was already half-asleep and then it was hot and our windows were open and so I wanted to think it was a draft. But it happened both yesterday and tonight, when I went to bed with the windows closed because it was cool. I told Mom that I constantly sleep badly here, but she says I'm just not used to the new apartment yet, even though for example when we went to her friend's dacha last week for 3 days I slept great there, in a separate room alone on the floor because Mom and the friend slept on the first floor.
Also from what we heard in this apartment together with Mom, when we were sitting eating in the room, from the hallway there was a sound like shoes falling on shoes and as if moving, we heard the sound together, but Mom said, when we went to look, that it was me who threw my sneakers anyhow when I came back from a walk and they slid onto her shoes, though I know I didn't do that. Also when we were in the room, there was a crash in the bathroom, turned out it was her hairdryer that fell from the washing machine in the bathroom, even Mom was surprised, because she always puts it in the same place by the wall. Also in the hallway the laminate often creaks by itself, like when you step on it - we also heard it together. And this weekend at night I went to the toilet, when Mom was already home and asleep, and there all her underwear, which she had hung after washing on the dryer, was lying in the sink, it couldn't have fallen there by itself, because from the dryer to the sink it's about half a meter. I hung it all back, otherwise Mom would have later decided that I did it.
But I'm writing here because of what happened today. Mom came home from work at twenty to four, I wasn't asleep as usual and was just lying with half-closed eyes and happy that now I'd fall asleep, because in the room I wouldn't be alone with the weird crap anymore. She took off her dress, hung it on a chair near the dining table, drank some juice from the fridge, went to the bathroom, came back and lay down on her bed. After that I fell asleep. And in the morning her dress turned out to be lying on the floor almost by Mom's bed about 5 meters from the chair she hung it on in front of me. And it wasn't just lying there, but was neatly smoothed out. Mom was the first to see it and decided that I did it on purpose, I of course said no, but she didn't believe me and we even quarreled. We have an agreement not to lie to each other and I keep it, and Mom got offended that I, as she decided, lied, like, as she said, there are 2 options, either it flew there by itself or I did it and she hasn't heard of flying dresses.
It's because of this last case that I'm writing here now, Mom has already left for work, my mood is shitty and again I'll have to fall asleep alone with this crap.
I reread what I wrote, sorry that it's a bit crooked and long, but I think I didn't forget anything. Surely there are experts here on what this entity in the form of a gnome might be and what can be done so that all this crap stops?