Congrats about being newly pregnant!
I'd think your reaction to that party seems pretty normal. I get that way when I have to hang around my family/relatives when it's all about drinking. Then they talk about how great drinking is and you can tell how it's turning them into these relaxed, super happy people and my AV is just screaming "Let me out! Let me drink tooooooooooo!!!!!" It's hard to feel neutral to the AV at that point so I usually remind myself that I'm actually not like these people that can drink because if I drink now, two months down the road my life will be a train wreck again and that helps me get a grip and ignore the AV again.
If you hadn't been to a party like that with alcohol so predominant for a while too that'd explain it...probably why they say on the AVRT thread to tease your Beast in tempting situations so you know how to take it when the day comes and it catches you off guard.
And for the sake of being crabby today...last day of my vacation
...I'd like to add that the people were possibly assholes for bragging about drinking around someone pregnant...at the very least they could've made one without the alcohol for you which would've been equally, if not more, tasty.