My 4 month old was solely breastfed for the first 3 months, I am now back at work and pump during the day, I don't pump much, a bottle every two days, so my baby takes a good amount of formula at day care. We recently discovered he refuses a breastmilk bottle. We have given them to him before with no problem but recently everyone who has watched him has had problems including us this past weekend. He cried till we gave him formula. I will note he nurses from me with no problem at all. Is this normal, can I do something to change this, feel like I pump for nothing.