Re: Returning to work and breastfeeding. Baby 14 weeks old.
I wouldn't bother getting her in a routine now, it will only stress you both out and when she transitions to her babysitters house the whole routine will fall apart anyway. It is best for breastfed babies to be given smaller, frequent bottles when away from mom because it more closely mimics the nursing pattern and is less likely to interfere or cause problems with nursing. Here's a great article you could share with her about how to bottle feed a breastfed baby. A bottle warmer can be used, but I always thought it was easiest to just place the frozen or cool milk in a cup full of warm water. The only major no-no is that you don't heat it in the microwave.
If you feel your caregiver isn't going to be flexible with you, it may be worth looking into other options. You are paying her to care for your child the way you want your child cared for; she should be the one listening to you tell her how it is going to work.
“We are not put on earth for ourselves, but are placed here for each other. If you are there always for others, then in time of need, someone will be there for you.”