I'm not sure what AFS is but FAS is Fetal Alcohol Syndrome. You can google it if you wish because I'm not going to be the one to describe what can happen.
I wouldn't be too concerned though. I drank a nice bit before I found out too, and my doctor said that it'll be fine. I know a girl who drank, smoked, and did weed throughout both of her pregnancies and her babies turned out just fine.
I think as long as you aren't chugging back a flask of vodka every single day of your pregnancy, you're probably okay.
But you've stopped now and that is all you can to do!!! You made a responsible decision and I am sure you will be rewarded with a healthy baby for it
Talk to your doctor though if you have any more concerns.