Is it normal that i still love a girl that doesn't love me?

I grew up with very few friends and I never made any meaningful connections until I was 15. I only had a slight interest in girls, which caused both family and classmates to claim I was gay, but it was only because I hadn't found any girl that was smart and could make me laugh. In high school I met a girl through Myspace that started talking to me a lot, and I'll admit she bored me like everyone else at first, but after a while I found out she was really smart and funny and I enjoyed talking with someone for the first time and I thought we grew really close (which she actually said herself a few times). I'm not sure when but at some point I pretty much fell in love with her, and as soon as I did problems began. She made it very clear she didn't want anything deeper (I'm still not sure why), and over the course of a few years we had a very confusing on and off friendship. I actually made a few attempts to grow closer to her later on when I was in a better place in life yet she still acted like she was holding back. At some point I grew sick of it and it started bothering me just seeing her so I started looking for reasons to hate her (and I found quite a few unfortunately)...and that caused me to stop talking to her, thinking I could leave her behind and move on. The problem is...I'm here six years later and I haven't really moved on. I still think of her a lot, regardless of how she may have hurt me or the choices she's made. Isn't that stupid? It just seems so wrong that I could still care a lot for her when she made multiple opportunities to show me she didn't feel the same. I've secretly dated since then and talked to numerous girls but none of them have interested me in the way she did. I don't know what to think. Am I stupid for trying to make an awesome friendship turn into love? And is it weird that I still feel the same no matter what the truth may be?