Possessive of my home, or overreacting?
	
	
		I'm 17, when I was 16 I became best friends with this girl named Katey. Her and I were really close for about five months, then we stopped being friends but agreed to remain on neutral terms. Once summer started (we weren't friends) my brother moved in, I left for camp (one week) and when I came back her and my brother were really close. I noticed some of my clothes were missing, and I saw Facebook pictures of her wearing them. I left again for camp (this time for four weeks) but got sent home twice for an illness, both times her and my brother were really close, and I assumed they were sleeping together. When I got back for good I confronted my brother about it, he got really mad at me and threw things. I called her and she didn't answer, I sent her a rude text out of anger. She refused to talk to me without my brother around. So, we talked. They admitted they were sleeping together. Her and I would be civil to each other. But now, I always come home and she is there, and she is cleaning my house, cooking food, and is there more than I am. I am so mad! This is my house, not hers! She makes grocery lists and everything, she even tells my dad when were out of something. My brother is almost 20, and shouldn't even be living here, I feel like this is no longer my dad and I's house, it is Katey and my brothers house. I want to explode with anger! What do I do?