Why can't i stop thinking about this girl from high school?

A couple things before I begin:
1) I have aspergers
2) Was raised by a single mother and had a bad childhood. I wasn't abused or anything really, mostly neglected.
2) This led to crippling depression and anxiety by the time I hit my second year of middle school and realized there was something wrong with me

When I started high school, I had been in the local rowing club since 7th grade. One day a week or so into freshman year this girl walked in late to one of my classes and the teacher yelled at her. She's the most gorgeous thing I've ever seen, so I kept staring at her and eventually made eye contact which fucking destroyed me. I couldn't look into her eyes for long after that*

*It's hard enough making eye contact when you're an aspie, but when It's a beautiful girl that you're crushing on, there is just no chance

Couple things about her:
1)Short
2)Big boobs that she was pretty self-conscious about
3)1 year/grade older than me. This made it hard to get a read on her social standing, but she seemed very friendly and outgoing and I mostly assumed everyone in her class liked her and every guy she talked to wanted to date/have sex with her.

So she ended up joining the same club as me that year with her friend who was a year older than her (2 older than me) and also very nice and pretty but overweight. She immediately started talking to me as soon as she could. I just stuttered half-answers and mumbled because I was confused and socially inept*

*By this point in my life I had not a shred of self-confidence and wasn't much more than a scared little animal in constant fight or flight mode, I could barely think straight and never knew what to say or do with myself

So this went on for a couple years. She would come find me every chance she got, whether I was sitting alone somewhere or walking alone in the hallway at school, or what have you, and talk to me and touch me and compliment me and all that. I couldn't tell whether she was just screwing with me or what, but she melted my brain into a puddle and made the temp go up 20 degrees just by being around me. I could barely come up with answers for her. I either avoided looking at her or stared at her chest, which probably bothered her but I couldn't look her in the eye and I didn't want to stare at my feet either.

She was pretty perceptive and I think she noticed that there was something wrong with me. She asked me weird questions like if my parents got along (they pretended they did but I knew better. I told her they got along fine anyway). I did and said a lot of stupid things around her as I stumbled blindly through social situations, but even when I was unintentionally mean to her and avoided her she wouldn't leave me alone. When we were getting a ride home one night I started silently crying in the car from the tidal waves of stress, and even though she was talking to other people behind me, she noticed and put her hand on my shoulder. That was pretty much it for me. I had to admit to myself that somebody else actually cared about me, even if I didn't know why.

She eventually graduated and left. Then I left. Then I spent a few years learning how fucked up I am and dropping out of college and trying to hold a job and going in and out of the mental hospital. That's kind of where I am now. I'm 21 now and I've been thinking about this girl since I first saw her at 14. I've desperately tried to stop thinking about her, but she made me feel something that I never felt before or since. She planted something in my mind. I don't need this right now. I have enough to worry about. But this isn't the normal crush it needs to be to fade away.

Shit I'm tired.