So there's this girl whom I used to like. We have a few classes together and we used to be friends sort of. We talked, laughed, had a few connections (I think) etc. She asked for my number one day and I gave it to her. I thought about asking her to Prom but after realising she sort of acts that way towards most friendly guys, I realised I had no shot so I asked her friend instead, who happens to be a very good friend of mine as well.
And now the problem: Lately she hasn't been friendly to me at all, before it used to be smiles, laughs, questions etc. Let me illustrate how it is now, she asks weird/random questions, and ignores me when I ask her something.
For example out of nowhere in math class she whispered to me I needed to get a corsage for my date, which I told her I knew. And today she asked me what color my tie will be, also during class, out of nowhere. I asked her what her dress was like and it went like this:
"So did you get a dress yet, what color?"
"What color is your dress?"
And then she goes off asking the teacher some question without asnwering my question.
It's pretty much like that, she even asks me something and then it's like she's not listening to the answer sometimes.
I'm going crazy, am I overthinking it? What do I do ? How do I act towards her? Should I do that to her as well?