Weight gain

Catherine
So I'm not a small girl to begin with. With my first son, I gained 23 pounds during my pregnancy. This is my second pregnancy and I'm 38 weeks along and have only gained 8 pounds, which is all belly! I'm actually happy because it's less weight I have to take off after the baby is born. The doctor said the baby is growing fine but yells at me for not gaining weight. I eat when I'm hungry so what's the problem!?