Problem at work with assignments?

i am a certified nurse assisstant at a nursing home, and everyday 3 cna,s are assigned rooms by the nurse. i have the same section, there are 3, and it has gotten easier because some of the resisdents don,t require much care. ..the last day i worked,, the nurse now has assigned me 14 resisents because its easier in my section, and the other 2 cna,s have 11.....i don,t think this is right, and am fairly angry about this.. the nurse did this partially because one of the cna,s have been complaining that i have the easier section...when i first started there about 1 yr ago, i had at one time 17, and the other 2 sections had 13, and its was a lot harder in mine..and no one complained then......i sort of hinted to the nurse a couple of times that i should not have had the one extra room and she took it away from me,,,,1 less resisdent, and she seemed irratated by it....i feel like going above my nurse to the director of nursing and complain.....what are your thoughts on this..thanks ron