I'm going to tell my sister I don't want to hang out after she walked almost 6 miles in the cold to get here and she brought me a donut
Why would you treat her that way after she's gone to so much trouble?
Because I don't like her anymore and need some space.
If your sibling has gone to a lot of effort and trouble to be kind to you, you should at least show her the courtesy of spending time with her. You will be ungrateful and rude if you ignore her after all she's done to come hang out with you.
I can't help any of this. I just don't like her anymore. It's frustrating when I don't get what my sister says.
Try to use this time with your sister to get through to her. You should notice the extra effort she is putting in to try to appease you. The more you communicate with her, the more you might learn about her behaviors.