Newborn baby only need to drink very little milk in the first few days, just like Ping-Pong size.
After that, you will start to have milk and must enough for your baby.
If baby finish, he will not suck and sleep or quiet for 1 to 2 hours.
You just need to keep relax, have regular meals for yourself and feeding baby when he cry in the first month, it's a great help to increase your breast milk.
I am not only enough milk for my own baby and can support other mummy.