Though you got a lot of great responses already about what baloney this is... I had to chime in.
Trust your body- women's bodies have been birthing babies and nourishing babies for centuries... otherwise, the population would have died out!!
You can do it. If you have problems, there are websites, lactation consultants, La Leche League, etc etc etc.... you have TONS of resources at your fingertips on how to increase your supply!
I'm studying for my IBCLC (that's a certification for lactation consultants) and am willing to help you anytime! The absolute best way to start your nursing relationship is to nurse your baby within the first hour of birth.
Also, my daughter was 8lbs, 9 oz, which isn't HUGE, but I had more than enough supply for her and I had to pump days and nurse nights because I returned to work when she was only 3 weeks old. Also, I was able to nurse her until she was 3.5 YEARS old with no problem.
Congrats on your bundle of joy, and don't be discouraged!
Here is a GREAT site for breastfeeding and other natural and attachment parenting: http://www.mothering.com/discussions/index.php
M.