I've been in the exact same situation before. I never regretted contacting the people. Even if I didn't hear back or they weren't interested, it gave me closure so I could move on. Otherwise, I would spend years obsessing about the guy.
The only regret I have is that the first time I contacted somebody this way, I was pretty honest about just how much I was thinking of them. It must have really scared the poor guy. I still get embarrassed remembering the e-mail I sent him, and it's nearly twenty years later. I learned from that experience that I need to tone it down.
I like the suggestion you got from the previous poster. Facebook is good because a lot of people like to have a huge friend network, so you're contacting her wouldn't even seem that odd. It's fine if you want to tell her you sought her out, but keep it short and simple. You can say something such as, "I was just remembering you as you always seemed like an interesting person that I'd want to get to know." Don't mention that you're thinking about her non-stop as that may creep her out. Good luck!
“This planet has - or rather had - a problem, which was this: most of the people living on it were unhappy for pretty much of the time. Many solutions were suggested for this problem, but most of these were largely concerned with the movement of small green pieces of paper, which was odd because on the whole it wasn't the small green pieces of paper that were unhappy.” ― Douglas Adams, The Hitchhiker's Guide to the Galaxy