Calories

When baby goes through a growth spurt, I feel starving! I mean STARVING! I feel way hungrier breastfeeding than I did throughout the whole pregnancy. I'm not sure how many calories it takes per breastfeeding but I imagine more than I consume. I've lost 25lb from the pregnancy on the first month and half, I'm still losing weight because I just can't get enough food in me. My little girl seems constantly starving and going through grownth spurts. Sometimes she nurses for hours!! I'm hungry again as I type this. Anyone else starving?