Guilt played a huge role in my breastfeeding struggles, and in those of many, many women I've interviewed. Or at least, I have always thought of what I experienced as "guilt".
Recap: Guilt = response to what one does. Shame = response to what one IS. As women struggling with breastfeeding, are we feeling guilt?: "I had a hard time balancing breastfeeding and work/older siblings/whatever"? Or - so much scarier - are we feeling shame?: "I'm a failure." "I'm not a good mother." "I'm not enough." "I'm not fully a woman."
I remember exactly what I said to my husband when breastfeeding my first child was ridiculously painful and hugely anxiety-inducing: "I'm a failure. Women have done this for all of human history, yet I can't do it." That was shame. That was me feeling that who I was just wasn't good enough for my baby. Or, maybe, not good enough, period.