full tummy

trying to keep Adler full these days we have added a tablespoon of cereal to her breast milk bottles. now, today i added a few ounces of formula to the mix as well. All of this in hopes to keep her full. We have almost gone though all of our back log of milk from when i was totally engorged and could pump 6 oz in 5-10 mins. Now at work i am lucky to pump 4 oz a time. this is not enough to keep her full when i am not around. I HATE supplementing with formula but i don't want hungry baby either. I am going to have to do more research on what can help keep my milk supply up. I drink at least 64oz of water between pumping/feeding and this is just not enough to increase my milk supply.