K.,
When my son was about the same age as yours, I experienced a similar issue with low supply. I was either pumping or nursing every few hours and I still couldn't get my supply to increase. I mentioned this to my OB-GYN and he gave me a prescription for Reglan. It worked for me! You only take it for a short amount of time (in my case, 2 weeks) to jump-start your milk production, and that's all you need. Here's a link to the info on kellymom.com:
http://www.kellymom.com/health/meds/prescript_galactagogu...
On top of that, I also drink the Mother's Milk Tea. So many women swear by it, and while I don't know if it REALLY works for me, I figure it's not hurting anything. So why not?
Whole grain oats are also supposed to help, so I eat healthy granola bars and whole grain oatmeal on occasion.
And the advice about drinking water is right on! I am not a water person... In fact, I'm not much of a drinking person at all. I could go all day on one 12oz. soda or one bottle of water, but pregnancy and nursing made me change that. You HAVE TO stay well-hydrated in order to keep this up. And when our pediatrician told us that our son gets a good supply of water from his breastmilk, that made me want to drink more water to make sure he and I both were getting enough.
I hope this helps. I know how frustrating it is to feel like you're doing everything you can and you're still not making enough. You're not alone! Good luck to you!
J.
Mommy of 8-month-old Ryder