Listen to InsaneApache.

Get on with your life and you will be fighting them off with a stick. You might even discover something better!

That small talk you described is not just being friendly, it is very mild flirting. But like most things based on pure physical attraction, it doesn't have any real meaning. You might be a handsome fellow, she might be bored, you might be the only chance she has, she might act like that with everyone.
Be aware that throughout High School and generally in educational situations, a young girl does not spontaneously approach a young boy just because she is feeling friendly. There is always something behind that and they will never admit it, as you wouldn't either.

I think this is really causing you too much stress and distraction to be any good for you, if this is something which is taking you away from study.

You should know this by now but sometimes a flirtatious conversation is struck up just because the girl likes that curious little adrenaline rush that comes with the tension. This happens all the time, it gives the ego a boost, it gives a hope for the future and it is deliciously ambiguous. You get it too, don't you?
That may be all there is to it. And unless she makes it obvious that something further is on the cards, it isn't worth thinking about for another moment.


That's it, she could just be feeding off your fear. What a succubus. Time to focus on more important things.