not trying to be a buzzkill, but this girl doesn't sound that trustworthy?
Giving you hints, then moves to another guy. is with him for what, 2 weeks, then says she doesnt' have feelings for him and puts her tongue down your throat.
Sounds like she's kinda playing with you both. Not that I know her in any way, but know many girls who've done that kind of stuff to my friends - be careful.