You met her and within two weeks sent nudes about which you're obviously uncomfortable and arranged a date? And you're surprised she dropped out of contact? You're new to this, aren't you?
I'd say it was too much too quickly and she's overwhelmed. It could certainly be a family emergency of some sort--and somebody she's not met in person and has only been messaging for a week or so isn't going to be a high priority for notification.
I'll offer some suggestions for future interactions.
•No more than two messages of any sort in a day. Doesn't matter how exciting you find the interaction, you're likely responding as much to the idea of finding somebody new as to the actual person.
•Hang back about meeting people in person. Allow time--and this is measured in actual days and weeks and not by the volume of words traded in messages--for eveybody to process through the initial rush of excitement prior to stepping up the intensity.
Time is your best friend in keeping things manageable. Adolescents rush into things blindly; adults show a bit of restraint based on understanding how these things work.
•If you're uncomfortable with the idea of people seeing nude images of you, don't send any until you've known the recipient for a long while. Period. That, for most people, is a major step and not something to be done shortly after meeting somebody else.
Just so ya know: I met my ex-wife via online personals in 1995. I met my current wife and gf via online personals. I've had a profile online for most of the years since '95 and have met lots of ladies--and had lots of them drop out of contact suddenly. I've learned to measure interactions by milestones and it has helped maintain my sanity in the face of it all.