If she:

>rolls her eyes at you
>doesn't try to initiate any conversation whatsoever
>tries to avoid you
>doesn't smile at you ever even when you smile at her
>doesn't let you touch her hand when paying or grabbing your food
>walks away before you can start a conversation with her
>looks annoyed when you pull up to the drive thru

If she has done any or a few of these things it's over. Just walk away and try to find a new chick.