What the hell is this feeling?

I have a crush, I confessed to her but I don't think she thinks of me that way. Well, she hasn't really given me a response to it so I took it as a no. I can live with that. In fact, I'm not really looking to courting her even if there was still a chance because we'd be better off as friends. But then I still get jealous at the thought of her dating other people.

It is so selfish of me to think like this. It's as if my brain is telling her "It's okay if you can't be with me, just don't be with anyone else, okay?" I'm on the fence of moving on or just accept that I could pine for someone but just don't do anything about it.

Anyone got a similar situation and what did you do about it? Thanks