Why am I scared eating with someome at school?

First thing is that I am a really shy person.... � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � I am really scared eating with someone at school. Like cafetirias and such. � � � � � � � Im a 2nd yr. high school by the way and new to this school. � � � � � � � � � � � � � � � � � � � �Last semester at my old school. A new student, I feel that he really want to eat with me, but didn't give him a chance. i told him Im waiting for my cousin which is true but one time. My cousin was late so he asked me again why am I so lonley so I have no choice so eat with him. But he was really shy he was eating a really small snack and I bought a big lunch so I told him can I buy him some food but he rejects to. When Im eating he has that weird look in my face. So i didn't quit finish it. After that he never asked me to eat with him. He was actually a really fun person and we became really great friends but still I eat alone. There was a some sort of over night bonding a retreat like. we ate our food which is served like ones at home and the teachers randomly gave us our permanent seat for eating. I ate like a gentleman like ALWAYS. I sat with 3 girls and our weirdo classmate. We talked and i gave pathetic jokes. But they seem to laugh they were really nice to me. � � � � � � � � � � � They gave me the same reaction. i can't picture it but its weird to me. I ate with no one at the whole sem. � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � I want to get rid of my weird problem . If you dont understand my horroble grammar or english and there might be some wrong spelling, Do not answer my question. Can you give me some things to help me like tips..or how do you eat with people......call me weirdo but thats me.....Im really friendly when im comfortable with people BTW