Cat help?? Serious answers only, please.?

[Kutay]

So ever since we moved to my brother and his girlfriend's house (they have 2 cats) my cat has been a total betch. She always hisses and gets really aggressive, unless she's in my bedroom (the other cats arent allowed in there). Once she comes to the living room or any other room she gets all sneaky and angry and rushes to the door to go out and gets really aggressive. I try to pick her up and move her from the door, and every time she kneels down to he ground, hisses and tries to attack my face. She never, ever used to do this, so why is she acting like this all of a sudden?we've been in this house for at least 6 months. she's allready familiar with the other cats, and even tried attacking them on many occasions. she's not scared of them, sometimes i bring them to her and she just sits there and stares at them. the other cats never try to attack her, one's kinda simple and just minds his own business and the other one hisses and runs away. ITS scared of her. Sometimes she comes out here and lies on the ground and chills, only time she gets aggresive is if i try to pet her or pick her up.

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