Living with my best friend

So my best friend is living with me at the moment until her mom gets things better in the house. She’s staying with us by order of social services. It is honestly so hard and she has been with me now for 2 months (possibly 3 more months MINIMUM). It’s honestly so stressful and I am having such a hard time with this. She has been getting on every last nerve of mine and I need a break desperately. I’m the kind of person that needs to be alone sometimes and I sometimes need to isolate myself and have time to think. With her being here it’s impossible and its starting to take a toll on me. Her home life was also a lot different than mine so her rules were different. She’s really mean to my little brother (he’s 9) and it’s REALLY pissing me off!! She’s also been rude to me to but her being mean to my little brother is what makes me the most mad. Trust me I know my brother is extremely annoying. I understand that. But she has no right to treat him badly like she does. This is MY home and I’m not going to allow her to make my own brother not feel welcome in his own home. Whenever I say something to her she gets upset and it causes problems in our friendship. I also never get any attention from my parents and when I do I really appreciate it and it makes me happy. I feel like when that actually does happen, my best friend tries to steal it and make everything about her. She also does a lot of little things that annoy me but I don’t want to say anything to her because I don’t want her to feel like I’m doing every little thing to hurt her feelings when I’m not. Another thing is she swears 24/7. She knows I don’t like and there’s nothing wrong in my opinion with swearing but it gets annoying when she says fuck in every single sentence. Like she just complains all the time and is super negative. I understand that things are really hard for her right now and I do feel bad for her. I myself feel bad for feeling this way about everything but I can’t help it. Another thing that’s really hard for me is when I’m in public or at school I always smile and laugh and pretend to be happy when really I’m actually really depressed. It gets exhausting having to pretend to be happy and cheerful at home now. Before I could just come home and not have to pretend to be happy all the time. I wouldn’t have to force a smile and I could just be alone for a bit. Whenever I look at someone I always give them a smile to let them know I acknowledge them and so I look nice. But it’s getting so so hard to keep up that fake smile and pretending like nothing is wrong. It’s getting hard to keep laughing whenever she shows me something or says something trying to be funny. It’s so hard to just smile anymore. I don’t know what to do. I’ve had a talk with her. Things got better for a week or two but things are just going back to when things were taking a toll on our friendship. I’ve talked to my parents but they don’t seem to understand it. My advice to people is that the best way to lose a friend is to live with them. So right now I’m really depressed and I don’t know what to do anymore.