I had osteo fortnightly in my last pregnancy, and weekly by last few weeks. I was only on crutches once, unlike my first pg.
Have you looked into the Pelvic Instability Association? They meet monthly in Malvern, but have a website and Facebook page.
Also, get a doc to write a supporting letter for you to take to the council to get some home help. They will try the line about permanent or long term disability, and if you insist about having a young child and no transport or other means of home help they will likely do something, at least until bubs is born. You don't drive, so a disabled parking permit won't be necessary (unless your DH has a car, then you'll want one so that he doesn't have to carry you into places!) - GP can help you organise that, as well as your council office (you'll need both - GP first).
And make an appointment with your hospital's psychologist. If you've booked into the hospy as a back up plan then you should be able to avail of this. Otherwise, the MCHN should be able to refer you to someone, or your GP. Dealing with sudden incapacity is a helluva thing to come to terms with. I still don't cope well with it. I'm useless and COLD here if DP's not here to split firewood - that's a sure fire way to get my pelvis angry with me!