I have recently started exclusively pumping for my 3 month old son and I am worried that my milk supply will drop quicker than if I were actually nusing. Is it true that your body can tell the difference between pumping and nursing? I am using the medela pump in style, pumping every 4-6 hours for 10-15 minutes, getting 2-4 ounces from each breast. When I was both pumping and nursing, I would easily get 4-5 ounces from each breast. Is there something that I can do to keep my milk supply up?