ADVICE! a girl from work gave me her number and now she doesnt answer? read on...?

I am 18 and a girl at my job, who is 20, at Office Max where we both work at gave me her number and we have gone out twice now, once to the movies and once to eat and then we hung at her house and stuff and we always talk at work and have fun. I have called her sometimes to hang out again and to chill but she didnt answer her phone and didnt call back. I understand that we both work a lot and are busy and she has school in the mornings but she could have least called back right? Please give me advice because after all she gave me her number and we talk a lot at work and stuff. ThanksADVICE! a girl from work gave me her number and now she doesnt answer? read on...?
she just changed her mind... so don't bother thinking about her, NEXT! =)

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