I'm Pregnant and still need to lose weight!

So, I've been losing weight for about off/on 4 mos now and I'm already down 20lbs but I just found out that I'm 5 1/2 weeks pregnant! My ultimate goal is to get down to 140 to 150's but I know I won't be able to do that pregnant. I'm currently at 200 and i would like my weight around 180's or less for a healthier pregnancy. I talked with my dr today and she stated it is safe for me to continue to lose weight while I'm pregnant as long as I'm eating healthy and exercising. Has anyone had succes doing this? Any thoughts or ideas would be helpful! Thanks!