help please 😩😩😩😊

mother of 2 πŸ’–πŸ’™
So, this is my 2nd child & with my 1st child was so easy to breastfeed cuz I had milk as soon as I had the baby but now with my 2nd child I don't have milk at all... he is 3 days old, what should I do? I put him on my breast to help the milk to come out but nothing yet, I have a pump, but can I pump without any milk? I'm drinking a lot of water & nothing 😩😩😩