Drinking While Pregnant

I just found out I am pregnant, only about six weeks if I'm calculating right. I was not trying and it's actually quite a shock. I'm just really concerned because since I didn't know I have drank alcohol twice. The first time was about three weeks ago and it was ALOT. The 2nd time was a few days ago right before I found out and was only two or three drinks. Just curious if anyone knows if I would be at risk for fetal alcohol syndrome. I'm terrified and feel very guilty.