Alti is completely right,
You might have added too many damsels. They don't necessarily ALWAYS die. I cycled my 12 with 2 green chromis and they are happy and healthy today.
What probably happened, from the sounds of it, was your live rock had alot of dead things on it which in turn spiked your levels and killed off your fish. Did your rock smell when you put it in? My rock didn't smell when i put it in, ie fairly cured rock, and i believe thats one reason they did ok.
Either way you can let the tank sit for a week in a half and go get the levels tested. It seems your rock will take care of the cycling.