I have been breastfeeding since birth and used to be able to pump 100ml +. My son is now 8 months old, has been sleeping through the night for months and has 4 breastfeeds each day along with solids 4 times a day. I haven't tried expressing for months and thought I would this morning but have only managed to pump about 20ml. My son is a very happy and active baby, but now I'm a little concerned about my supply? Any advice?