I was thin at the beginning of my previous two pregnancies, but I'm heavier starting out this time. I am just about the same weight that I was when I delivered #2 4 1/2 years ago, which is almost 50 lbs heavier than I would like to be. I know being overweight and pregnant isn't a good thing, and I'm nervous. Is there anything I can do? I know I can't diet while pregnant but I am trying to only eat healthy foods. Should I begin a workout regimen?