Am I a selfish bitch?

My husband has been working a lot lately and I wanted us to have a romantic dinner, so I bought some steaks and some wine to surprise him. My sister has four kids and sometimes when she needs a break she will ask if they can spend the night. I had her kids everyday last week. Today she texted me asking if they could spend the night, but I told her me and my husband are having a romantic night. I set the table and was excited to see his face. Someone knocked on the door so I answered and it was my sister with her four kids and their bags packed. She said she's sorry but she can't do it day. She barged into my damn house. I told her I had her kids everyday last week and they can't stay the night tonight. She started saying she really needs help and a break, but I gave her a break for a week. All I wanted was alone time with my husband. She starts arguing with me about how selfish I am. How she's asking for help but nobody will help her. I had my nieces and nephews all week last week! All I wanted was one day with my husband. So instead of my husband coming home to a dinner he comes home to me and my sister yelling at each other. We argued for a good 45 minutes until I told her to just leave. She called me a selfish bitch and said she hopes when I have kids everyone leaves me alone to rot. Our dinner was cold and at that point I just wanted to go to bed. Am I really a selfish bitch?