Most Helpful Girl
Emotional instability, emotional immaturity, and a lack of self awareness. The possibility that she has someone is still possible but not valid therefore its irrelevant. Sometimes girls stomp stomp stomp till they get a response from the guy she likes. I'm telling you if she didn't like you, it wouldn't phase her out that much. There are so many possibilities, she can be just using you as a distraction, she could potentially just realized how much she digs you and she got scared, so she acts aloof. Maybe she doesn't really know relationships, thereby playing "hard to get" don't wanna look desperate or clingy. Also could be fronting that she does, maybe its all in your head and she thought of you as a friend or maybe its the fact that she talked to some girlfriends and she heard bad things about you, or they said he sounds like a loser , lets go out a guy hunt! , she wants you to c hase harder, yaddy yaddy all irrelevant till you confront her about it.
"Can we talk? I felt a sense of distance and difference from you, is everything alright?"
if she's mature she'll be honest about it if not she'll make it look like you're over thinking. In that case, drop her, a relationship can only be healthy if two know how to confront others and deal with things than to stew things in and have unrealistic expectations.