Wow it sounds like you and I have/had the same issues. I noticed once the baby came, I just couldn't hang with some of my less child-friendly friends anymore. Sadly, what ended up happening is we became excluded with everything because I was avoiding people my entire first pregnancy. It was easier that way, honestly. This is the natural progression of things and you'll learn who your real friends are when baby comes!
I was sort of expecting it - but once the baby came, not now It's also disappointing because in the 5 years we've been here and also been the only cigarette smokers we always tried to be considerate around others, and now it seems like a few of our friends have "suddenly" discovered weed in a way that I find quite pathetic, and they can't even stop and think before lighting up. I mean, they can do whatever they want as far as their health goes (well, I will judge them a little - mostly because they're acting as if they were 18 having the first sips of forbidden alcohol instead of twenty somethings with their own independent lives); but it seems pretty unbelievable that it won't be obvious to them that lighting up with a pregnant woman around is a no no (if we were outdoors I could sort of maybe perhaps understand it, because I could just move away, but not indoors).
I guess I just expected nothing much to change till the baby got here other than me getting tired early, so this was an eye opener and not in a good way.