Alcohol before realizing pregnancy

knottie6a9b4b3e6890bcd8

First time pregnant - I did not realize until 6 weeks because of implantation bleeding. I rarely drink. I am a 30 year old female.

However, at week 4, I had 1/2 a beer.
At 5.5 weeks for my husband’s birthday, I had 1/10 or a 1/12 (basically one sip) of a beer. All before finding out. Haven't drank since.

I have since gone into an anxious spiral about the thought of causing the baby alcohol related birth defects. I know it is just my ocd mind playing games (I am working on it in therapy), but something about the “no safe amount” guidelines is really throwing me off. I realize there are reasons they (governments) don't set a safe minimal threshold but still... freaks me out a bit. Realize the odds are like scientifically negligible... but just looking for some peace of mind that this half a beer, or sip of beer scientifically (100% without a doubt) could not harm my baby at 5.5 weeks.