She showed me interest then ignores me?

Met this girl in my sciences class in late August/early September of this year, she sat next to me the first day (she is the one that started talking to me) and we pretty much became friends, even thought we never saw each other outside of school, she was only a classmate but not a really close friend but now recently after showed obvious signs that she have liked me she suddenly started to ignores me out of nowhere and I didn’t do/say nothing wrong to upset her and I noticed that she will interact with everyone in class but act like I don’t exist😔But now I’m too nervous to engage a conversation with her to figure out what went wrong and it really hurts because I miss her and I have feelings for her and I know she have some for me too. Is she playing a mind game with me? Why she suddenly acting like this?
She showed me interest then ignores me?
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