I have another question?

hey moms and moms to be.i had a doctors appointment today and i got the shock of my life.when they called me in to check my urine blood pressure and weight my nurse told me to step on the scale first because she had other patients.when i stepped on the digital scale it hit 164.5.my jaw dropped open instantly.it sounds good and all but im only 19 weeks and 4 days.at my last months check up i was 154.8.i gained like 10lbs in 1 month alone.when i finally got called to see my midwife she of course told me that im gaining to much weight to fast and escorted me right away to the nutritionist.i sat down and spoke with her and she said im suppose to only eat 3 meals and day and snack like 2 to 3 times only.i tried to explain to her that i do eat 3 meals a day and snack.but i still be hungry and she did not seem to understand.i don't eat a lot of junk and i don't even drink soda.i don't know what caused me to gain so much weight in one month.im 5'4 (this i found out today) and my starting weight was 146.im not a over weight person.my arms are still bony and i always had thick legs and .the only place that seems to be getting bigger is my belly.i even found out today that im having a boy (im happy) and he weights 11 ounces already.my question is what do i do when i eat and im still hungry? should i be really worried about how much weight im gaining? i eat plenty of fruits and veggies.Is my baby boy going to be huge? how much did you gain when you were pregnant? does it really matter how much weight i put on? thanks i appreciate all the answers. if this helps im 20 going on 21 and this is my first baby.