Crush. Just a passing infatuation, as i see it.. it'll pass
soon..
Theory: single, hoping to find significant other to fill the 'gap'
in your heart.
Therefore, as you meet girls with 'eligible' attributes, you become
smitten and become lovestruck..
I'm not saying that meeting someone in that way is bad, but that
may be why you're missing her and such. Since she's attached, you
can still link up as buddies or sth..
May luck be with you.