Re: 15mo lost interest and supply dwindling
What you do now is up to you. If you think that increased supply would result in more nursing and you want your child to nurse more, and you're willing to pump- then pump. If you don't want to pump, or if you're not that wedded to the ideal of getting your child to nurse more, or if you think your baby wouldn't nurse more even if you had more milk- then no pumping or other supply-building interventions are necessary.
Basically, with an older baby, how you manage supply and weaning is a lot more flexible than with a baby who is less than a year old.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"