@marcuslarcus,
She didn't let you know and you didn't call her to check if she could go, waiting and suffering apparent rejection, then feeling miserably rejected?
You overthink.
She may have a lot going on in her life.
She might have not taken it as some kind of for sure Date.
Her letting you know would have been thoughtful, but she also may have figured that you would get it wasn't happening as she didn't confirm.
She might not be all excited about going out with you. This happens.
We don't know what she thinks.