Opinions? Arguments with mother and sister?

Today we were in town with my mother and sister. After we had finished what we were there for, I asked if I could get a drink. My mother said it would be unnecessary to drive further into the city center. I googled it and saw that 10 minutes by car would be enough time to get the drink. So my mother said okay. My sister drove and we went there. On the way we saw a restaurant. Then my mother said she was hungry. We decided to eat something first and then get something, so we went into the restaurant. Unfortunately, there were problems with ordering and we decided to leave the restaurant without eating. I then complained because we are customers and the employee kept trying to push us to go to the buffet, while we wanted to eat normally. My sister also tried to explain, but the man didn't understand. When we left, I was very angry with the man and complained very loudly and enthusiastically. My sister thought I was mad at her. Maybe it came across that way. I explained to her that I was mad at the man. Then she said I was behaving like a child. After that we went to the car. We got to the shop where I originally wanted the drink. Then my mom said I could get it now. But I'd already lost my appetite after the whole argument with the waiter. So I said no and said I didn't want it anymore and that we could go to the car. Then my mom freaked out, and so did my sister. I only came here because I wanted this drink and now I don't want to eat. I didn't understand them because the plans changed afterwards. We all wanted to go out to eat together. And after the argument I just didn't want a drink anymore. I called my sister stupid because she accused me of being mad at her, even though that wasn't true. So I made my way back quietly. Then I decided to say that what my sister and mother had done was unfair. They admitted to themselves, and the whole issue escalated. Then we were in a supermarket. They started ignoring me. I said it wasn't cool. My sister then said I was exaggerating, in a very loud tone. But I kept talking. Because I was very angry and didn't want to say anything wrong, I got out of the car and left. My mother called. I answered and said I was going to walk home. A few minutes later, I saw her. She came over to me and said they were worried. I was angry that they hadn't respected my privacy.