Why do I still have feelings for "Chuck" and I never had a actual chance to be his girl?

Well, I met "Chuck" in 2005 when attended the same college in Las Vegas, but he left in 2006 and in between that short time I developed a very intense infatuation for him, something that I still deal with today (I still can look at his pictures online and still feel that nervousness that I felt when I first met him). So, after the many attempts out of desperation and frustration to tell him how I really feel about, they all ended up rejected, the most famous response being "I like you but as a friend." So, now its 2009 and I still feel the nervousness, but not as much as I used, but its still there. Can someone answer for me why do I still have these feelings for a guy that I never was in a relationship with, yet I wish I was. Why do I hate him one minute, can't stand to look at him at all, or even want to speak his name, but I still find myself in the same instant melting whenever I run across a picture of him. Someone please tell me that I'm not delusional and there is something that I can do to stop thinking about him