Why doesn't my cat like to be in my room?

My cat is rather whimsical and she's only 4, but at my old house, she would beg to come in my room, and now I'm at a new place, and at first, my cat loved to be in my new room but nowadays she just refuses to go in my room and runs after me if I try to at least pet her by my door. If she does come in my room, it's like she's terrified and walks lowly and cautiously, like there's something after her. Someone explain why my cat doesn't like my room anymore and why she's like this?