Hi Melwood, I completely understand! I'm in a similar position - 28, pregnant, live in London, have spent the last ten years partying with my friends. My partner (34) and I are one of the first in our group to start a family.
About a fortnight ago, I was at a great 30th party and I burst into tears because I suddenly felt strangely jealous of my friends' freedom. I had to go and find my partner and have a secret weep in the corner.
I try to remind myself that I can still party - as in - I can still hit the dancefloor, make good conversation and have a laugh. I tend to head home once everyone gets too drunk, but at least I can 'sparkle' early in the evening.
In fact, I'm off on a big debauched weekend in the countryside this weekend - out of thirty people going, I'll be the only person not drinking!
I've joined a pregnancy yoga class and it is GREAT. Lovely teacher and nice to meet so many waddling ladies who live in my neighbourhood. It takes a bit of courage to say "want to swap numbers?" but that's what we're all there for.
But I also treasure my old friends, because I need people to remind me of the old days and who know me on a deeper level than being "so-and-so's Mum".
Also, I think us first-in-the-group ladies 'pave the way' for the rest of our friends. So hopefully we can give advice when our friends all start popping sprogs in a few years.
Good luck, and I'll keep reading this post with interest!!