Is this girl stalking me?

One day at work I was walking back from lunch. I noticed out of the corner of my eye her looking at me and walking fast as if she was trying catch me. She did. She came in from another door. I walked in and she turned to me and smiled at me. Weeks later we crossed paths at work and talked a little and got her number. (Which she seemed excited to tell everyone about). Days later we sit at lunch and she asks me where I get all these crazy energy drinks from. Which was suspicious considering this is the first time drinking one at work outside of my car. Made me think is she looking inside my car while im at work?
Is this girl stalking me?
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