I just wanted to comment because I am a sleep deprived nursing mom as well. This post was very encouraging to me, because I feel like I'm not alone in being up at night feeding. My 6 month old son is up 4 times at night, and eats 20-30 minutes too. I've been told my pediatricians and nurses that he is capable of sleeping through the night, he doesn't need the night feeds, etc. However, I disagree. I continue to night nurse and tell myself that "this won't last forever" and that "I will miss these night feedings when he's in school."
It's hard running on empty as a mom. BUT, you are doing such a great job in meeting your child's needs! Don't feel pressured into doing something or sleep training just because other's are telling you what they think is best for you and your child. YOU are the parent, and you are doing an awesome job!!!