exclusively pumping moms?

Erica
So this is my third baby and decided I want to try exclusively pumping. I formula fed the other 2. I am worried about those couple of days before my milk fully comes in...what will the baby eat? I understand it would be best to attend a class but working full time with 2 kids (one being special needs) makes it impossible to attend any classes on breastfeeding! Any advice from moms who have exclusively pumped would be awesome!