Struggling with understanding whatever it is I'm feeling, would appreciate opinions

This might be a weird post for this sub, but in my experience, everyone here has been more helpful than on other subs. I'm a freshman in university, a month and a half into university. I've made myself as outgoing as I can, although I prefer to do most things by myself. I'm confident, I can talk to people, whether or not I do depends entirely on my mood. I met a girl by chance on instagram a few weeks ago, we met up in the library on campus for a quick study session. We've been talking ever since, almost everyday, either texts or phone calls. The phone calls have been long.

I've noticed that I start to feel uncomfortable when we're on the phone for long. Not because of what she says, or the questions she asks, in fact I'm struggling to understand why. She seems like a nice girl, I'm not attracted to her, I have no idea why I start to want to pull away. She speaks a lot more than me, she asks me all sorts of questions, when I say "goodbye" she asks "why," and I don't know why I feel whatever it is I feel.

I know all this sounds super incoherent, and also makes me sound like a total ass, but I'd appreciate help. Thanks.