How soon is too soon for rice cereal?

I know that it isn't recommended till the baby is close to 6 months but I actually started adding it to my first daughters bottles when she was about a month old. Well now my second daughter had been doing great. She would eat 2-3 ounces every 2-4 hours. Now the last day and a half she has woken up to eat at least every half hour to an hour and a half and will drink anywhere between 1 1/2-3 ounces. My fiance is no help at all and I also have 2 other kids I have to take care of throughout the day so my sleep loss is making me go nuts...

Has any mommies started adding rice cereal to their newborns bottles any sooner than a month?