D.C.
What I understand is that amount of milk produced is based on "demand" not on how much you are drinking water (or whatever). The less your baby breastfeeds, the less the supply (although, this is so unique to each individual).
Strangely, trying to breastfeed less by offering to nurse less can lead to plugged up milk ducts. That can be painful but can lead, easily, to an infection -- which you would want very much to avoid!
Pumping has a weaker sucking action than your baby's. This means 1) that it might be harder to "empty" enough so you don't feel the unpleasantness of being engorged and also means 2) that your body is getting the message of less demand.
I have heard quite a few ladies proclaim lots of help from cabbage leaves. Hope they help you.
You can get very good advice and counseling from a local lactation consultant. Your ob/gen doctor may have a reference to someone or may even have such a consultant on staff. I'm talking about someone accredited by the Board of Medicine and, often, is a nurse.
Good luck!