<human>: Can you succinctly summarize the text in 1-3 sentences?

There is a girl in my friend group at school who I developed feelings for a while ago. She told me she just liked me as a friend. Prior to that, I had only developed feelings for her because I was positive she liked me, her friend had told me she was sort of interested in me, so I went in thinking I had nothing to lose.

Months later, I am still confused and upset. We flirt constantly, and she acts different to me than to the other guys in our group. I really can't take it anymore. I love flirting with and talking to her, and even my friends who were unaware of our brief history have recently said we have some great chemistry together and that I should do something about it (how ironic). I make her laugh all the time, for minutes straight, and I feel like I am truly myself around her. Also, I have dated one other girl since then but nothing too serious, and my friend said she seemed visibly jealous by that.

Like I said, I can't keep doing this. I keep deluding myself into thinking something will come of it. She gets everything from me hanging out with her in the group (humor, my personality) whereas I gain nothing but delusions. However, it's not like I can just leave her. Our group is very small and close, with only two girls, and I really like the other people in the group, and they are my close friends here (possibly why she didn't go further with me in the first place). What do I do? I will be absolutely crushed if she ever finds someone else. The only way I have gotten over this feeling in the past is by leaving the girl behind, but that's simply not possible here. 

Btw, she probably has no idea I still harbor feelings, aside from the flirting. I think she thinks the whole thing is in the past.
<bot>: My best girl friend rejected me, and it upsets me to be around her. I can't tell if I'm hoping for something that will never happen.