Leasha this is the same thing that Vic and I have been having since much earlier in our pregnancies. Pelvic Instability - and yes it is completely normal for third trimester. It is one of those things though - you either get it, or you don't!

Pilates, physio, osteo, support belt and my OB also recommended acupuncture, but I haven't tried that one. The rest I do and although some days are more painful than others, it has remained manageable. Which is great, seeing as my OB told me that if it gets too severe I would probably need to be induced early. Some people end up in wheel chairs or with a walking frame.

If you google pelvic instability a website comes up that has some great advice on managing it. Things like avoiding bending (I rearranged my kitchen to avoid bending as much), avoiding stairs, keeping your knees together etc. Take a look!