Firstly, my sympathies. SPD is excruciating and it sounds like you have it bad.

I would suggest using ice instead of heat. Ice any aching bits regularly, it really helps. Secondly always try to keep your knees together, tie them with tights in bed if you feel you need it (with a pillow between them) to stabilise your pelvis at night. And thirdly, rest. Don't try and do too much. Don't walk if you can avoid it, and try not to go upstairs or uphills unless there is no alternative. I think the hardest thing about SPD is the fact that you are really disabled and people assume you are just making a fuss, so psychologically it hurts as much as the physical pain. Hopefully you will find some ways of coping soon