P.S.
I had problems with my son gaining weight too and my Pediatrician suggested supplimenting my breastfeeding. What my pediatrician wanted me to do was suppliment with formula, but I took a different approach instead. I went on the Ben and Jerry's diet. I ate a small bowel of ice cream after every meal. By the end of the week, when I took my son back in to be weighed, he had gained 11 pounds. I only had to do this for two weeks to get my milk nice and rich for my son to gain weight. I also started putting 6 diapers on my changing table every morning. If my son went though them all by nighttime I knew he was getting enough of what he needed.