I'm quite overweight myself. Despite recently losing pounds due to diet and exercise I still have a good 60-65 pounds to lose before I am at a healthy BMI. I lost 25 pounds over the last year, gained back about 5 lb before getting pg this time and I've only gained 4 pounds so far in 12 weeks. I was even heavier when I got pg with both of my kids. Not ONCE did my doctor ever say my weight was going to cause for concern with my pregnancies. I have not tested positive for hypertension or GD or anything. My only pg complications have been from low progesterone levels. And, through healthy food choices (LOTS of fruits and veggies, stuck with leaner proteins when I could, and just watched my carbs a bit more) and moderate exercise (walking mostly), I kept my weight gain with both of my kids at 20 pounds. So don't worry.