Is he trying to make me jealous?

There’s this guy I like and he really likes me back. He flirts with me, acts like a true gentleman. And even told his family and friends about me. One day however I was sitting next to an old guy flame. We never dated but I used to really like him. Anyways I was talking to him a lot and we were laughing and giggling a lot. One day I noticed my crush who sat behind us look mad. I had asked him for help on an assignment question and he didn’t say anything. I wasn’t sure if he heard me or not or if he was just ignoring me so I said his name louder just to make sure. He looked up mad. He gave me the death glare and just said “no I don’t know the answer to the problem”. Anyways days later there was a new girl who came in. All I would see him do is flirt with her stare at her in FRONT OF ME. I wanted to cry I felt like I loved him or cared about him. And I thought that he felt the same but why would someone who feels the same about you do that. Also during this time I think her told his dad about me cause I went to a football game where he was playing and all I see are him and his dad staring and smiling at me as I walk by. I don't know what do you think
Is he trying to make me jealous?
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