Don't wait a minute longer. Just get on with finding someone who is anticipating your next date and not avoiding you like this girl is. If she's not pursuing you back then you're wasting your valuable flirting time with better prospects.
Desperate people wait so let her call you and in the meantime, foreget she exists.
I've also gone ahead and sent her a message on PoF (where we initially met) this morning asking if she received my text yesterday.
She likely has 50 other guys emailing her. You've already contacted her.. it's her turn to contact you back and if she doesn't then ... Next!
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion