Feeling beaten up today

This morning I slept until 11 a.m. I never sleep that late. I am usually a morning person. But after yesterday, I guess I needed some rest.
What do you say to a sibling who doesn't want to talk about something that's happening in your family but unleashes all the mean-ness she can muster?
Yesterday was my usual break. My sister has volunteered to come for a few hours one afternoon during the weekend so I can get out of the house. She has been showing up between 10:30 and 11:30 a.m., but yesterday she didn't. I got up early, showered, washed my hair and ran to the grocery store before Mom got up. Then I made some egg salad so Mom could have some lunch with Martha. I was going to stir up some cinnamon rolls for some friends, but when I looked at the clock it was getting close to 11 a.m. so I didn't. By noon, my sister hadn't come or called, so a little after noon, I called her. She said she had finished exercising and was at Hallmark getting a birthday card. She arrived a few minutes later.
My rolls could've been raising in the pans by the time she got here.
Before I left, I said I was going to get some apples a local produce market.
That's the first thing I did was get some of their wonderful sweet juicy apples. And although it was a little cool, the sun was shining so bright and inviting that I drove to Rainier to a local Amish furniture store to look at their beautiful furniture and dream a bit. Then I drove to a mall, parked and called a friend. After about an hour on the phone with her, I stopped to get some Chinese food and went home.  I was gone about three hours.
When I walked in the door, I had the apples in a bag and my Chinese food. My sister and Mom were sitting on the couch.
I put the bags down and sat down in the living room and my sister looked at me and said, "Well, I don't see any apples!"
It took me a minute to digest what she had said and then I shot back, "Well, Martha, they're in the kitchen in a bag by the refrigerator."
"Well, I guess I'm leaving," she said and left. As she walked out the door, I said, "Goodbye, Martha," and she replied, "Goodbye" in a tone that said, "I never want to see you again."
I didn't cry then, but my feelings were really hurt. What I had done now? And why did she say something like that? All questions that will remain unanswered because Martha will NOT talk about what she's feeling about Mom and what's happening to her. So I don't know if she didn't want to come yesterday and felt obligated or if she just needed to take out something on me or what.
All I do know is that I was so hurt.
If she doesn't want to continue to be with Mom on the weekend, all she has to do is tell me and I can make other arrangements.
Later that night I watched a movie about a dog and at the end I was just bawling. The tears just came and came and wouldn't stop. I know it just wasn't about the movie, that it was just all the crap welled up in me about the day. I think the well got pumped out last night. I even emptied a box of tissue.
So this morning, I woke up and my whole body felt like someone had punched me over and over.
I guess it will take time to heal.
And I am so looking forward to going to the neurologist because my sister will be joining us. I wish she wouldn't come at all. She just adds more stress.