So I don't know what to do!

Whitney • Proud mom of 3 year old baby girl and baby boy due in December.
I went for my 13 week prenatal. Everything with baby check out great heart rate of 160. I am a plus size woman I weighed 215 when I got pregnant. I weigh 218 now. My midwife said that if I didn't gain any weight that would be great. How am I not supposed to gain any weight??!!! I am always hungry and I eat lots of protein and vegetables.