Ziasha, yes I did get a call
And I did inform the chapters that I would not be attending; I didn't just not show up. It seemed that a lot of girls did the same since some of the parties were held at the same time, and even with the option of leaving halfway through a party to attend another one, many girls wanted to stay at a house that they loved.
At my school, informal rush usually consists of girls going to whichever houses they choose (parties are advertised in the school newspaper and whatnot), and then chapters call you back to invite you to further events. This year, Panhellenic just took it a bit further and added the first day where we went to 8 houses.
Now it's time to go to class, so I'll update when I get back from my chapter event tonight. Hopefully this will all end well and you guys can stop worrying!