A girl that I like called me a nut. what does that mean?

so the girl that I like called me a nut. I don't think that she knows that I like her. I was just siting there in one of our classes talking to her I don't remember about what but nothing that she could call me a nut for. I mean we barely talk to each other. we've formally known each other for only 3 weeks. is her calling me a nut I sign of flirting or just some thing to say?
A girl that I like called me a nut. what does that mean?
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