My jealousy issues is getting so shit

I had a crush on my best friend of quite a few years. We talk quite often and had some flirt enuendos.When we were in diff classes, the crush started hanging out with a girl, laughing with her and sometimes going home with her. This was fairly recent. I feel insecure but I don't understand what is so special about that girl because I have everything that girl has and I'm better.

I'm not sure what should I do lol I look dumb