I am also breastfeeding my 14 month old and I didn't lose a thing until the last couple of months. My problem was that there was no time to get to the gym and going for walks in the winter is nearly impossible with a baby (and a preschooler) where I'm from, so I was taking in more calories than I was burning. I went back to work and now have a bit more time to get to the gym and track food, but it is still really slow to come off. Even with my first, I couldn't get the weight off very easily until I was done breastfeeding.
I think the reason they say that you lose weight by breastfeeding is because it can burn up to 500 extra calories a day producing milk. So if you eat those extra 500 calories, the weight won't come off. I know I was eating at least that in cookies every day!!