Friendships are tough when you move about. I got married in 2006, I was 32. At that point, I still had all my school and uni friends, and some really good friends I had met in my first job. I pretty much thought that would be it, that I would just add friends as time went on.
Not how it worked out.
Since having children, I have virtually no contact with my school friends, most of whom are childless. My uni friends moved away, one by one, and although they are still "my friends", we email a few times a year and meet up only every other year. One of my best uni friends and I totally lost contact, she started an affair and after months and months of talking it through with her, I started to distance myself. My chief bridesmaid and closest female friend moved to South Africa and I have seen her once since then.
I did the toddler group thing TO DEATH, I threw myself into it body and soul, I "mumdated" from the evil place that should not be mentioned Netmums. I went to classes, day (with kid), evening (without). I made some good starts, but people went back to work and it would fizzle or never get beyond recipe discussions etc. I met a really lovely local mum and lost her number when my toddler threw my phone into the toilet at the same time that I had to change work days and not go back to the same group.
Not sure how you make yourself a community. I have some friends, enough to chat to or meet once every six weeks or so for a meal, but no one very close that I could really spend a lot of time with or go away for a weekend with. I'm a sociable, outgoing person but it requires SO MUCH TIME and it can so easily become impossible when people's availability changes, as it tends to do with p/t working.
I feel for you, I am there too!