A.M.
Babies really cannot be put on a sleep schedule until they are AT LEAST 4 months old. Infants needs upwards of 14 hours of sleep a day, and may do so in various increments. The term "sleeping through the night" really means 5 hours, and ideally babies, especially breast fed babies, need to eat every 2-4 hours. It sounds to me like your little one is just doing what babies do best -- i.e. change up on you jsut when you think you hav a routine. This is nothing to worry about; although you may be tired. As for the nanny, i am glad to hear you switched -- babies need interaction, touches, love and care to thrive and just letting her sit in a seat all day is concerning. Best of luck.