Hey man, sometimes its natural to just hug a co-worker upon their leaving, without any further expectations. For example, when I resigned a job years ago, I gave a big hug to my secretary (she initiated it) but it was just a friendly "good bye" and there was never any implication of further involvement. She was married, and I wasn't the least bit interested in her sexually, but she was a friend nevertheless, and the hug was warranted, but I knew it was just a "going away" gesture.
Your friend has all the info she needs to contact you, but I agree with a lot of the guys that have said that she's busy getting ready for college, and once she gets in college, she's surrounded by guys her own age that live nearby. Going away to college is the great divide between high school and college age people.
Don't sweat it man, you're young, and have millions of girls to ponder a future with.
