I'd like to revisit what the doctor said in the hope that it helps. You said he said "he cannot quantify the risk but that we might still be okay." There is nothing "extra" in this statement than what you already know. It is 100% true that medical knowledge is not at a state of being able to calculate a probability for fetal alcohol damage during early pregnancy. Most of the data regard women who drink, excessively or not, throughout their pregnancy. In terms of medical research, these are the easier ones to find and study. They can track them either prospectively or retrospectively and calculate risk for having fetal alcohol syndrome. Women in your category are much harder to find and so the data probably do not exist or are weak. The other issue, that I mentioned earlier, is that women who have a binge during this time may "miscarry" and no one - including the woman - ever know they are pregnant because it happens very close to the time they should have their period. So although the way he said it ended up not being comforting, the basic facts are that no one knows. It could be a possibility---one that there is no science to rule out---but it could also not be a possibility.The other confounding factor is that many health problems are not "caused" by a single factor, but many. When we say that such and such causes X disease or syndrome, there are usually other (more confounding) factors involved. If something were to have happened, it would probably be a combination of the binge drinking episode, genetics (from both parents), and a small nutrient deficiency. (I am just making this up.) But as a fellow mother, and member of the worrying club myself, you've got to find relief in the fact that you only control a small % of that scenario. None of us are perfect.
We can't ever perfectly plan our actions for every conceivable outcome. (heh-heh.) Please, please give yourself a break and don't resist this fact of life but accept it for what it is. We all must. I truly believe your baby will be free of any major health problems that could have been prevented by your not drinking. If there are other (minor) problems, like a learning disability, this single act probably didn't "cause" it. Sometime later you will realize that part of the path of becoming a mother means learning how to accept the problems of others with compassion and moreover, to accept yourself as well. As someone prone to perfectionism and anxiety like you seem to be, this was the greatest gift. I am not sure I could have learned it without becoming a mother. Now that I am expecting another baby, I am not that worried about problems (big or small) that might be on the horizon with the next one. (Obviously, I don't want there to be any problems. But I am not actively worrying about them.) I have accepted that this is part of the gift of life for both me and my child. Truly, everything is going to be alright.