What if I have no chance?

I have, no joke, liked this girl for 6 months. And I’m in 8th grade, so its a long time. I have already gone out with her, twice, but I havent now for months and I miss her every time I move. I dream about her, I write about her, and basically she penetrates every pore of my body. She’s in most of my classes but I cant seem to ever get to talk to her. Sometimes I think she’s smiling at me, but its always just at a joke someone told her. I’m starting to lose hope. She’s dated like 5 guys but none of them lasted for more than about a week (both times we lasted 2 months, the second one was 3), and I cant help wondering who the next one will be. On the rare occasion I do get to talk to her all I can do is stand and smile dumbly and her jokes, without cracking any of my own. I’m known for being a funny guy, (that was how I got her before) and without that I’m nothing. I know how to get over nerves and stuff, I’m usually a total flirt, but around her… things are just different. It’s like I want her to like me so bad that I can’t do anything about it. Also her best friend has liked me for quite a while, so I know she knows I exist. I’m thinking that I pretty much have no shot of getting her back again. Is that a good assumption? I know hope springs eternal, but mine is running dry. Please, if you have any advice for me, give it. -Charlie