oh poor you! i can totally relate to the mourning for friendships lost, by life changing and being pregnant and friends drifting away etc. And when you are feeling so down, it makes it even harder to go out and connect with new people :-(
its a time of upheaval and change and of new beginnings, and it can be utterly overwhelming - and thats just the stuff about YOU, let alone the fact that you're going to have a baby too!
i think that why a lot of people over prepare for it all, to try and get some sense of control over a totally new and non controllable situation. thats why I'm saying don't stress too much over not having fallen into that trap!
what i found was that everyone is in the same position, once id got up the courage to go out there and start smiling at people, i found that lots of people were equally keen to make friends and meet up. Its a really special moment in life, when friendships aren't so closed and tied down, and its ok to say, 'hey, i don't know anyone, fancy meeting up?' without seeming like a scary stalker!
i did the nct thing as i was soooo terrified of not knowing what i was doing, and spending my mat leave alone with no one going through the same thing as me. The info was nice and comforting to have, though ultimately didn't help that much (except the trying out nappies on a doll, that helped!), what did help though was finding out that all the other mums were as nervous and worried as me. I also met people by going to the cinema (the one you can bring your newborn to) - that was great cos if i was feeling shy i didn't have to talk to anyone, i could watch the film and go and not feel like i was sticking out in any way. Also in cafes and in queues and waiting rooms, and at post natal physio too! New mums seem to be on the watch out for other new mums too, so although i wouldn't dream of talking to strangers normally, the whole vibe was a bit different. Having said all that, I am not bestest friends with them all now, but i am good friends with 2 of them, and thats plenty for me!
sooo, what i am saying is that its OK to be scared and alone, but if you just manage to get up the courage to go do a 'first time mum' type of thing, then you might find it easier than you think. AND its def not too late to start. would it be less scary if you A. took someone else with you to a meet -up or B. went to something that you DO something at, so its not all about the pressure to socialise (like the cinema thing etc). Can you frog march your dh to a NCT meet up in your area (they sometimes do just 'come have a coffee' things rather than having to do a whole expensive course)? OR will you tell mums net your approximate area, then maybe we can recommend the places to go that mums go to? if all else fails, have the baby then turn up to the local 'mums' cafes/ parks etc, i found having a new born was the ultimate ice breaker!