Not sure why this happens... I usually get about 16-18oz for my 5 month old baby girl in an 8 hour stretch at work during the week. I pump first thing in morning Sat. and Sun. to keep up my freezer stash. Like clockwork, my output dips on Mondays to 12oz. It usually comes back up the next day. Does anyone else experience this? Do the girls miss the baby or do they just need to adjust to the routine again?