Crush? Lust?

Hi everyone! Hope you all are doing just fine; keep up the good spirit! I'm at war with myself; call it a "dilemma" if you want :D Well, as you've read in other posts here on Ahwaa (you didn't read my posts?? SHAME ON YOU :P)...well back to business... I mentioned earlier that I was in love with a girl (my ex-best friend); who's married now. It's been for over a year now that we've contacted each other; I guess everyone moved on with his life. Anyhow, a few months ago I met this girl. I have no idea wether she is straight, gay or bi? I don't get any vibe...the only vibe I get is: I WANT TO BE WITH HER! She's gorgeous and I can't stop thinking about her. We've met a couple of times, but she's in a foreign country now...completing her study abroad. I don't have the guts to contact her on FB (yes..I kinda searched for her)..because I don't know what I'm feeling. I don't know if she's just a rebound, or that I'm truly crushing over her, or just fantasies of lust. Has anyone experienced such a dilemma? Please, tell me...how do you know when you truly like someone (like a crush) or you just wanna experience them (lust)? .