It is very common that breast milk come after few days of baby’s birth.
Usually your “pre-milk” will come in right away and be ready to go day of the birth, this is called “colostrum” and is brighter/yellower than the full milk that comes a few days later. The white milk came in like a week later and it was totally fine, baby breast fed colostrum her first week of life and gained weight appropriately. Keep in mind a newborn baby has a teeny tiny stomach so they don’t need a lot of volume the first few days but they will want to breastfeed very often since they can only consume a small amount at a time if that makes sense.
In the hospital, the baby needed extra feedings due to jaundice, they wanted her to take in more calories to help pass the bilirubin faster, so they told me to supplement and gave me the option of formula or “donor breast milk”. Breast milk donated from other women that has passed infectious disease testing. I choose the donor breast milk and uses that for just two days until my baby’s jaundiced was gone and she no longer needed it.
If your colostrum for some strange reason doesn’t come in or if you need to supplement ask about donor breast milk at the hospital if you want to avoid formula.
What is more, to speed up the milk flow, you can use the breast pumps to massage your breast. Usually breast pumps have two different modes. The massage can help to stimulate the milk.