It's so difficult and we can all absolutely relate! In your situation, if they are all people who care and are supportive (and who you'd likely share any news with whether good or bad) I might go with something along the lines of:
"So, you may notice I'm not drinking tonight... It is what you think but the timing is slightly off as I was hoping to share with you tomorrow after my - hopefully positive - 12 wk scan... As it is, I'm feeling extremely nervous, especially after last time. I'd appreciate if you could hold off on the congratulations until we've seen how things go tomorrow."
Maybe just say something along similar lines to people individually/if they comment about you not drinking, rather than a big announcement to everyone. For what it's worth, the odds really are in your favour. And I know that's a bit meaningless when you've fallen foul of them before but it really is most likely that everything will be fine this time so try to hold on to that 💗
@LER2023 sorry you're in limbo. Hope you get a nice clear (hopefully positive!) result on Sunday. X
@Ella31 symptoms can come and go. Hope yours return soon to reassure you a little, although from personal experience unfortunately the high and reassurance of a positive scan and even symptoms don't last long in the first trimester. You just have to plod on day by day hoping and believing in the best until proven otherwise. Do you have any more appointments booked in ahead of 12wk scan? You've got this, keep going 💗