my daughter is 8months old. This weekend my dp ...

my daughter is 8months old. This weekend my dp is looking after our dd . but all today she would take the bottle of breast milk i left. she uses that bottle with water in it all the time. so when i got home at 5pm left at 7am she had only drank 100mls. they poppped down at lunch time to give her a feed. i dont know what to do tomorrow