kittykat I'll be having to get a new cot and mattress most likely as DS will only be 16/17mo and still in his cot when this one comes and Moses baskets only seem to last a few weeks before I get fed up with them!
10 I had SPD start with DC2 at about 36 weeks and just had the painful turning over in bed and getting up. Then with DC3 it started at 20 weeks. I wasn't as bad as some women get it; needing crutches and painkillers etc but it was shit. I dreaded going to bed, getting up, moving from sitting down, just moving really. It started with more of an ache deep in my hip joint and round toward the pubic bone. And my hips made clicking and grinding noises. Then the pain just got worse and worse.
Saying that though my hips have always clicked when moving from certain positions. Since last pregnancy the clicks are more frequent though and louder. Have to say I am a bit worried about SPD this time.
Post birth wasn't fun for a while either last time. I think it's partly due to being on my side to have DS and someone held my leg up and probably too much. Partly because my hips hurt so much during labour. And then partly because I was in stirrups for stitching which I shouldn't have been really. But after DS popping out a bit too quickly and weighing what he did they were very carefully checking me over. It all settled eventually though. The physio did something to try and align my hips up a bit after birth which helped and then after that it was just time they needed.
It's probably more likely the ligaments doing their thing on you right now 10 but I'd keep a close eye on it and get yourself referred to physio if needs be. If you are starting with SPD it's a long haul from now until 40 weeks. Just keep your legs together a lot when getting out of bed, in and out of cars and things like that. Pretend there's paparazzi waiting to take a pic of your pants at every given opportunity 
I know this has turned into a long post but i wanted to say this too: don't feel like you're being self pitying. Even if you were (and you're most definitely not as I'd be getting tearful at all that work and travelling too) this is the place where you are allowed to be!
Hope your exam goes well