What kind of diapers do you have? You might be careful with the Dawn because it does void warranties. I usually do it in the bathtub and then throw it in for about a million rinses. RLR works great too and isn't nearly as intensive. If you use BGs they recommend bleaching once a month and that's great for getting rid of ammonia.
Re: grrr...ammonia!!!
I'd hold off on using dawn just yet. Ammonia can be from detergent build up...and dawn is another detergent.
First, what kind of diapers are you using?
Second, have you tried to strip using just hot water (or boiling if it's prefolds or anything w/out snaps and elastic)?
Third, what is your wash routine?
I think something may be up with your water or wash routine since ammonia after less than 3 months (if your ticker is right) is pretty quick.