My sister brought a random woman to live with us in our bedroom and sitting room apartment and i have no space now

Post:

I live with my sister in a one-bedroom apartment. Recently, she brought a woman I’ve never met to stay with us. I was not asked or informed ahead of time. This woman has been here for days and I’m not sure how long she plans to stay.

The apartment is very small, and I no longer have any space or privacy. She is messy (dirty dishes, clothes everywhere) and very loud, especially late at night. I feel uncomfortable in my own home and I don’t feel like I can relax or use the space normally.

I’ve tried to express that I’m not comfortable with this, but my sister dismisses me. I don’t know my rights or what the best way is to handle this situation, and I don’t want conflict, but I also can’t live like this. And if i leave i dont know where to go and i dont have enough money to rent a house . Am really going crazy because the space is small. And my sister isnot listening to me.

How can I set boundaries or ask this person to leave? Am I allowed to?