People laugh at me when I run?

The one thing I am afraid of doing than talking in class to answer something is running. Early in the school year, I was in between fast and slow. And for some reason whenever I run, I tend to get nausea and ending up throwing up. But I never told anyone, but now it seems like everyone is laughing and rolling on the ground when I run. Then I stopped running in school no matter what. But, I was in gym and went over to my best friend to confront him with the earlier stunt he pulled on me. Then, this girl who loves messing with me came up and tried to chase across the gym. She stopped as she saw me running and everyone started to laugh. I walked off feeling sad and didn't know what to do. Later, she came up trying to chase me again. Instead of running, I walked slowly and people keep yelling at me telling me to run. I didn't listen to them so I kept on walking when my best friend started to chase me. He pushed her into me and then I started to run. The girl fell on the ground and laugh while rolling back and forth. My best friend stood their laugh and almost choke. I don't know why people laugh when I run. I don't find anything funny about it.
People laugh at me when I run?
Post Opinion