My cat has been acting up recently and I don't know what to do. She's constantly following me around. She'll get up from her sleep and meow and run after me after she hears me coming. And there have been a few incidents which have worried me. She'll come at legs when she rubs against them, and she'll swat at me when I'm sitting across her. I can't just casually walk by her, I always have to crouch down and draw her attention away from my legs so she doesn't attack them. I feel like she's always watching me and I don't understand why. She's been watching me, meowing at me and following me around constantly. This was not normal before. I'm getting more and more scared of her. She's been seeking more of my attention lately.
Some info:
She sleeps on the floor instead of my bed now. She no longer has an interest in running out the front door when someone comes in. We brought in a carrier of another cat, could the smell of that cat be the cause for this behaviour? We haven't been able to get her wet food in a week and she's constantly meowing for it. Could the lack of wet food be the cause? Her behaviour has also changed quite a bit. We've had her for 3 months although she is 3 years old. Domestic short hair.
How do I get this behaviour to stop?
UPDATE: Ever since getting her wet food and removing the carrier, most strange behaviours have stopped. Thank you all for the responses!