Julie,
I too am in the middle of a fishless cycle and will be the first to agree that it is tough wating. My nitrates are all over the place, one day high and the next day low. From everything I read I think in your case the best advice is to stop doing the nitrAte test. Keep feeding ammonia to maintain ~ 2ppm and watch the nitrItes. They will come down with time ( so I am told ). After you have 0 on the ammonia and nitrite, you can do a nitrate test. It should be more accurate then and you can do the PWC to lower them...
Hang in there.