There's an SPD support thread here that might help, some lovely supportive women going through the same thing.
I don't have a toddler but I'm 28 weeks and have had SPD for some time. Been on crutches for 10 weeks already. I'm fortunate and bus stop is nearby but still find the reliance on public transport really tricky. I now do internet food shopping only and have also succumbed to a big online boots order for lots of baby bits and pieces. The internet is my best friend at the moment.
I've had to adjust to just being at home a lot which may be trickier with a toddler but I just suggest you try to get your head round doing as little as possible. Explain the problem to friends and family and hopefully they'll visit you. I've also considered patient transport options for MW appointments but not tried them.
Finally get yourself referred to Physio ASAP and hopefully they'll treat you, I've been seeing an osteopath who's worked wonders at keeping me comfortable and more mobiile, but it is costly and we've had to sacrifice other stuff.
Good luck. My only tip if you are using public transport is to carry a walking stick or crutch even if you aren't using it much, as it seems to be a magic talisman for people to realise you need help. (12 weeks and having SPD plus a nearly-3-yo who has to be forced out of his pushchair as I can hardly push it. I foresee many an afternoon on various pavements as he keeps staging sit-down protests...)
Have you checked minicab prices? Might compare OK once a week or so to the expense and effort etc of a return bus journey?