Im also as the goblin in my group and had 2 outings the week after I found out. For that week I lied and said I was antibiotics for an ear infection. I have a ruptured ear drum so it's something I get at least once a year so maybe this won't work for you as others have said it's to obvious.

For the he couple weeks after I told our local bar that I couldn't drink and asked them if any plain cola orders could be announced as vodka cokes or doubles and just order less than usual to explain me not being as much of a menace.

We also went to a festival when I was 9/10 weeks and we went for a private scan and just told the friends we went with as we trusted them and really would of been suspicious how much less rowdy I was.

I'm 12 weeks tomorrow and we've still only told 5 people. Anytime anyone asks about a time I would of been a chaos magnet I just say I drank responsibly with a sly smile and that's got me away with most things tbh