Just trying to be friends with everyone turned me into a loner

All throughout elementary school, I tried being friends with everyone I met in class. It usually worked out. I found myself trying to decide which sleepover to go to, who I would sit beside at lunch that day, etc. I once even had the entire class fighting over my crayons one day in first grade. Basically, I was a very social and friendly kid.
When fifth and sixth grade hit, there was this girl in my grade. We will call her K. We weren’t close, but I was just as friendly and nice to her and her group as I was everyone else. But when her group of friends became about half the size of my classroom, it all went downhill. I wasn’t huge, but I was pretty chubby in those years (I later found out that this was due to a thyroid disorder). K and her group would sit next to me and say, “Dang, J, you hungry?” I would look at them funny and say yes. Then they would laugh like it was the funniest thing in the world. She would do this almost daily. One day when she asked me again, hoping for a different response from them, I replied no. She said, “Then why are you eating? You still must be pretty hungry!” Then they would still laugh. It got worse from there. Anything I did in class, from dropping my pencil to my stomach growling loudly because I now refused to eat lunch, K and her group would just snicker and giggle and make some comment that would drive my anxiety through the roof.
This teasing spread like a plague. Throughout middle school, other classmates soon joined in with them and refused to have anything else to do with me. I had almost no friends by the time I entered high school. Although I didn’t develop an eating disorder, I didn’t eat breakfast or lunch, just dinner after school. And it’s still like that today. I can’t eat in public places by myself. I feel like everyone is staring at me and eventually I have to get up and leave even if I’m not finished eating, ESPECIALLY if I hear any kind of laughter. I am now in college, and I still just get my food from the cafeteria and eat it in my car or my dorm. I still have trouble maintaining friendships. And I still don’t eat as much as I should.
My final message: please don’t tease or bully anyone for any reason. You never know the permanent effect it will have on them especially during childhood.