didn't know I was pregnant yet...

Was anyone else drinking before they found out they were pregnant? I just found out I'm pregnant, and I had 1 beer on two separate occasions this last week (im 4 wks 4 days), but that's not what I'm truly worried about. About 2-3 days after I believe I conceived, I drank beer all afternoon/evening (football game). I've heard that drinking alcohol doesn't have an impact on the baby until after it has implanted (about a week after conception), so I'm hoping I'm in the clear!?