@chikitou,
You might want to look up the expression "in love with", as you are conflating a few possibly semi-meaningful looks with that. You have no idea why she was looking, Maybe you were trailing toilet paper on your shoe. You have no idea.
You had nothing with this girl. She owes you nothing, no explanations, etc.
And why are you having troubles dating other women? I dunno. Maybe you're obsessed with this one because it didn't go anywhere. If you start thinking of this whole hopelessly over inflated shadow of an experience as being you dodged a bullet, versus you blew your chances with the one that got away, you'll find you're a far happier person.