Keep, M was jaundiced too - we got sent back to hospital for blood tests when she was a week old and again at 2 weeks, but she was borderline so didn't get the blue light. In hindsight I wish they'd just put her under it because she stayed yellow for ages. At 9 weeks the HV thought she still looked yellow so sent us to the GP, who said she didn't see it herself, but better safe than sorry and made us an appt at the Sick Kids hospital. Where they basically went 'I don't see it', did a blood test, told us to come back in 2 hours and then gave us the all-clear. Bloody HV But the sheer horror of jaundice blood tests on a week-old baby as she howled and then the bloody nurse knocked the vial over and had to start again... 
And then had the gall to say that M was going to be one of those babies who screams so hard they go blue and recommended that we get her on a dummy! 
I hope your DD will be much better after her blue light.
Pen, sounds like SPD. Get thee to your MW pronto! I had this in both pregnancies and the MW will refer you to a physio. The physio will give you advice on what to do/not do to stop it getting worse. The second time around I got a lovely sexy tubigrip that went around the bottom of my bump and my hips to try to keep my pelvis together. Also a weird arrangement made of straps and lycra (a pelvic support belt) which was fairly useless as you couldn't wear it sitting down. In the meantime:
Behave like a lady at all times - keep your legs together. Honestly, this is the advice the physio will give you. When getting out of bed/out of the car, swing both legs around instead of putting one leg out first. Take stairs one at a time (ie, slowly, like an old lady).
Sleep on your side with a pillow between your knees, and one beneath your bump. The idea is to keep your top leg horizontal as bending it inwards puts stress on the pelvis. A body pillow can help.
Wear supportive shoes - no high heels or ballet pumps. This time around I am determined to find supportive work shoes that look smart and go with all my clothes yet are comfy and good for me...
Try not to carry anything on one side, such as a toddler on your hip or a heavy bag on your shoulder. Carry toddlers in front of you so they are evenly distributed.
Don't do breast-stroke when swimming or push heavy shopping trolleys/prams/hoovers. Leaning forward at my desk made it worse, too, so yoga balls can help you sit properly at home.
The physio will want to move your legs around to see when it hurts. This may not hurt that much at the time but later on you may be in agony. Go easy!
These things do help, but you have to be fairly religious about it. It does go away after you give birth, either immediately or eventually, but you need to watch your birthing position and don't give birth lying on your back with your knees apart as I did the first time. It went away the second time quite quickly but kept flaring up until I did a bit of Shredding. I think when my core strength deteriorates it comes back, which ought to motivate me to keep going.
Sorry for the epic post - Solars, sounds like you have amazing strength of mind! I would have been in the envelope before we got out of the car park!