Kirbstar - I don't know if it's the same thing but I have an unstable pelvis (caused by the release of relaxin during pregnancy). For me it did not disappear overnight and I have suffered it from week 28 until now (four months after the birth of my beautiful daughter). I hope yours disappears as it often can, soon after the birth but if not, the best advice I can give you is to get yourself to a physio that specialises in pregnancy stuff - I can PM you with some details if you like. Physio makes a huge difference.

Fiona