I am upset

Yesterday was my sister Diana's birthday. She came back from her university for the day, and she spent it with the family. We had a wonderful time. It was about nine at night when my mother decided to drive her back to her apartment on campus. My younger sister and I decided to accompany my mother. We had a fun time driving her back, with one exception. My mother started trash talking this gay guy whose mother is friends with mine. My sister and I both got riled up because we are both friends with him. After that "discussion" everything went well.
My sister was getting a little edgy, all of us were, it had been a long day and we were tired. We get to her apartment, and I help her carry things up to her room. Once we are up there, she tells me that she isn't coming back down, even though she hadn't said goodbye to my mother or sister. I go to give her a hug goodbye, and she pushed me away, and yelled at me to stop. It hurt my feelings, a lot more than I thought it would. As I am leaving, we both realize that she had left something downstairs. I told her I would go get it, and she would meet me halfway. So I run down to the car, only to find out that my mother was talking to Diana's godmother, calling all the way from Peru. I call her down so that she can talk to her, and the uh..."whining" begins.
She didn't put on a coat, when she knew that it was at least 3 degrees outside, instead she had wrapped herself up in a blanket. She started complaining that it was freezing outside, and she doesnt want to talk to her godmother. She is saying this while the phone is in her hand, and her godmother can hear everything she is saying. As she is complaining and my mother is yelling at her to just talk to her godmother, another problem starts. Her friend is across the street, and starts walking over to give her a birthday hug. Diana tells her that she is busy, and to not come over. Her friend keeps on coming anyway. Why? Because all of Diana's friends are attracted to DRAMA. By now, my mom is seething because of the way Diana is acting, I am trying to tell Diana to just talk to her GM, my other sister is in the background doing the same thing.
And then things blew up.
I called Diana an unattractive offensive word, because it is what she was acting like. She got upset and just hangs up on her GM, my mom gets pissed at her b/c she won't come over to say goodbye. I am sitting there wondering why I said it, while at the same time thinking, "that is exactly what she is acting like." Her friend is standing there with a friggin SMILE on her face, I hope she just didnt understand what had happened. And then Diana starts crying, and says, "but its my birthday." Then she runs upstairs, and we leave.
I guess I am upset now because I regret saying what I said. But only because I should have used another word instead. I know I hurt her feelings, but she hurt mine and my family's by not even letting us give her a hug goodbye. My mother called up her sister, Diana's godmother, after we had left her apartment complex. She was extremely hurt and upset, because she didnt understand why her only godchild had been treating her so badly. I didnt go out of my way to hurt my sister's feelings, or to ruin her 20th birthday, but I feel bad that it culminated in the way that it did. I feel like all of the tension that we felt in the car was because we were tired, Diana was cold, and emotions always run high in our family. I called to apologize to her, even though I don't think it was entirely my fault, and I left her a message because she didnt pick up the phone. I hope she can forgive me, and learn from her mistakes, if she even realizes that she has made some of her own.
peace
Ziggy