Is this girl trying to manipulate me or am I just confused?

A few weeks ago this girl started gaining attraction to me. After weeks and weeks: she would constant stare and me (sometimes looks away and sometimes stares), asks my friends where I am at when I'm busy, be nervous around me, her friend would giggle around me , always one of the first to click on my story and the biggest clue of all was my friends and I noticed that she looked me up and down and then blushed afterwards. Suddenly, she started avoiding me just in a day or so. Then she started going out with another boy, when she was talking to the boy she'd always be still looking at me even though I tried my best to avoid her (I've got to be honest I was quite taken aback by this). I asked her what was up and she replied with, "Do you like me or something?" Then I replied honestly that I was interested but she said that she was, "Just being friendly and doesn't view me in that way but she has someone else she views in that way." I then moved on, deleting all the texts. The next day I went back she kept trying to look at me whilst I ignored her in the corridors. I also posted a few stories on Instagram and she'd always be one of the first if not the first to see them. What is her problem?
Is this girl trying to manipulate me or am I just confused?
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