Get plenty of skin to skin time with babe, make sure you are nice and relaxed for feeding, feed as often as your baby wants to feed, even if it's hourly. Don't try to space the feeds apart to a schedule. You can express between feeds to boost your supply. Fennel / fenugreek is good, you can get it from a health food shop or naturopath. Make sure you are eating and drinking enough yourself.
Also just consider that your oversupply may have resolved, and now you have just the right amount of milk. Weight gain is not always steady, sometimes they have growth spurts and plateau's. Is your baby still having plenty of wet nappies and seems alert and well? If so then you have plenty of milk.
Honestly, breastmilk is the absolutely best thing for your baby, so please keep up the good work! If you have any dramas and need to talk to someone, ring an Australian Breastfeeding Assoc counsellor, it's free for everyone. Or see a lactation consultant, there should be one at your maternity hospital. Good luck!
Mama to an '04 boy