Feeling fat!!

With my first when i had him i was at 180lbs, with this pregnancy I'm going into my second trimester and I'm at 180lbs. It makes me want to really go on a diet but then I'd feel like I'm not giving the baby what it needs. I was in the progress of losing weight but been battling PCOS also. (which makes it hard to loss weight)

Has anyone else gone thru this and did certain things to help slow down the weight gain but still had a health baby.