I have only been BFing for a week so I hope this isn't a dumb question. People say when they exercise, their simply drops. How do you. Know? Do you only find out when you pump? What if you don't pump? I never felt my milk come in and I don't think I have ever felt a letdown so I am convinced my boobs don't function properly so I am worried that I wouldn't notice if my supply suffered. Thanks!