Thanks for your answers! It seems my milk is beginning to come in! I was very happy, but since I noticed it changing, DS is refusing the left breast and only eating sparingly from the right breast. I'm concerned this will affect his weight and my supply. I googled and found many reasons he may prefer one breast to the other and have tried several different nursing positions to get him to feed from the other breast, but it hasn't worked.
Is pumping the only way to ensure supply won't drop, or am I over reacting, since it's been less than 24 hours?
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DS was born 2 days ago. One of the nurses at the hospital made me feel pretty terrible about not wanting to supplement because DS was very fussy last night (she insisted it was because my milk hadn't come in yet, not due to gas, etc.). DS lost 6% of his body weight at the time of discharge (which I know is fine at this point).
Anyway, is there anything I can do to speed up milk coming in? DS nurses about 20-30 minutes every 1-3 hours.

Re: UPDATE to: are there ways to speed up milk coming in?/NEW QUESTION
It's normal for a breastfed baby to take up to two weeks to return to birth weight