Seemed disinterested now seems angry at me?

I recently met a girl at school and asked for her phone number. I expressed my interest in getting to know her better and she seemed receptive to the idea when we spoke in person. However, her behavior changed when we communicated over the phone. She was very distant never replied to my texts and eventually ignored my last text message.

After giving her some space, my friends suggested that I make an effort to speak with her again since I approached her. I decided to call her, but she hung up as soon as she heard my voice. I tried calling again, but she didn't answer. When I called using my friend's phone, she answered but hung up again when she realized it was me.

Given these circumstances, I decided to stop pursuing her. However, I've seen her around campus for the past two days. On the first day after the phone call incident, I waved and smiled at her, and she responded with a smile and a hello. Today, I did the same thing, but she seemed angry and her hello was low-pitched.

I am confused about her behavior and would like to understand what is going on from her perspective.

Seemed disinterested now seems angry at me?
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