I'm not the histology expert (Frayda, are you out there?)...but yes, I would think she is telling you the truth. Certainly we don't know your case specifically, but it seems reasonable that they are testing for differnet things, ruling out others...sometimes cells can be benign but they don't look normal....so they may require extra testing. When my noded were tested, it took 10-14 days. Doc told me up front of how long it would take, just some things can't be rushed. And in my case, all were benign, so the long wait meant nothing bad.
Try not to read into the delay.......i know it's hard, but hang in there!