It is very, very common for women to believe their supply is down when there is really no evidence for that. Another mistake people make is that the baby nurses for a shorter length of time. The baby in such a case has probably learned to nurse more efficiently and the mother is producing the milk far more readily to meet the demand and is having a good, fast let-down.
People worry about the lack of feeling of letdown.
Again, as you get used to nursing, often your breasts cope with a letdown better. The only true sign of letdown is that a nursing baby starts swallowing. A mistake I don't think you've made, but many women do, is that they get worried the baby is hungry and offer a bottle after a feed. The baby gulps it down and they assume the poor thing must have been starving. But babies are opportunists - if there is an extra meal that is very easy to obtain, they'll find room in their stomach somehow.