whithe cell count??

with my frist chemo my white blood cells went down to a 2.3..so they gave me neupogen.for a week to bring them back up..so i took the next treatment..and now they are at 3.5..and they said that was fine..and what me to take a treatment tomarrow..i'm afaird i won't have any white cells left..they said it shouldn't happen..but what if dose??? don't understand what's going on..dose anyone have a sugestion?