Life Advice

Near the begging  of June my parents took in my cousin because he lived in an unstable home. He was only supposed to be here for a few months, but it's turned out to be a whole lot longer. My sister, brother, and I love him but he's too big of a handful for us. My parents both work full time jobs so my older brother and I are often stuck taking care of him and my younger sister. Well tonight i finally decided that I'd had enough of my parents bull crap and I told them I didn't want to share a room with him anymore. I'm 15 & he's 6 and we sleep in the same bed. So my dad came in and called me selfish and told me he was disappointed in me... Am I being a bad kid by feeling this way?