Weight Gain

Since finding out I was pregnant in early October, I've gained 48 lbs. I have 56 days left before my baby is born & am nervous about my final weight. I know I was already considered over weight when I got pregnant & I did quit smoking cold turkey. But my dr is giving me the "watch the weight gain" speech. I don't want to feel bad about myself during this pregnancy - but it's hard not to let stuff like this get to you when you've always struggled with your weight - anyone else feeling this way? I'm planning on breast feeding & working out as soon as I can after her birth...