I am think it might be starting 
I am 21 weeks along and for the past few days I have been experiencing some discomfort in my pelvis.
Yesterday I noticed my hips pop with every step and while walking down the stairs I nearly took a tumble as my left hip gave out all together. I lost all srrength in my pelvis/upper leg area and was hobbling around in agony for a good half hour.
My pelvis aches when I sit down and laying on my side is so uncomfortable, also gives me a dead leg on the side im laying on.
I also noticed that sitting with my legs crossed is almost impossible now. It feels like a lightning bolt has shot through my pubic bone and I can barely walk afterwards.
Gonna phone the midwife tomorrow as I work in retail and am on my feet all day, its becoming a real problem.
Anyone have any advice on how to cope? Is there anything that can be done or do I just have to suck it up?