Hi P1
I have recently been diagnosed with SPD having experienced similar symptoms - I had never heard of it before
You can have physio via your MW - mine is making me an appointment - it can get quite bad if you overdo it so I have been told and as baby grows so take it easy.
A few tips in the meantime from me:
When the pain comes on don't try to push through it - rest up for a while until it eases - I find if I don't do this it becomes much worse and unbearable.
Try to avoid stairs and slopes (if walking outdoors). Walking on the flat isn't too bad for me when not in pain. As for stairs I live in a 3 storey house so have learnt to come down the stairs on my bottom and climb upstairs on hands and knees slowly keeping knees together as much as possible - not as challenging as it sounds
In bed, always bring your legs together when swivelling around to get out of bed and take your time. I am getting quite good at doing this half asleep for those through the night loo trips!
Getting in and out of the car can be a problem when the pain flares up - the carrier bag on your seat is a good suggestion as this helps you to swivel without using all your muscles.
Apparently a pregancy belt can help although I haven't tried this yet.
I found a useful assocation website somewhere a few weeks back I'll try and dig it out for you......
Good luck! It can be very frustrating if you are a fairly active person like me but listen to your body and you should be fine x