Pot while pregnant?

Tayste
I was a frequent smoker before finding out I was pregnant. I couldn't eat anything without getting sick, I was under weight and sickly and pot was the only thing that helped me keep food down. Since becoming pregnant, I have quit smoking but my doctor told me that there isn't now proof that smoking has harmed a pregnancy in anyway and that it helps with some of the symptoms (fatigue, nausea, constipation). She (though not condoning my smoking) said that it would be perfectly safe to continue. I'm not sure what to do. Anyone smoke while pregnant and it was okay? I'm afraid the baby will be affected my inability to keep food down, since I would be malnourished. But I'm not sure what weed will do. Anyone?