I am also one of the unlucky ones. It gets worse the further along I get. It's the hormones that are producing so that your joints loosen up. Some of us just get it worse than others. I start to waddle way before babies head drops just because my hips hurt to much to lift my legs. I sleep with lots of pillows to help. It will go away after baby comes.
Happens to me too since 15-16 weeks(now 22), specially after spending a lot of time on my feet. I have been taking it easy for the last few days and the pain is gone. Just doing light walks, no more than 20 minutes on my feet without a break of sitting down (and limiting total time of standing up daily to 2-3 hours). Oh, and prenatal yoga for the 2nd trimester, those stretches seem to help.
Am 16 weeks prego and going through that! It really hurts sometimes!
It's happened to me @ 23 wks preg from the joints loosening in the hips to make room for giving birth. I had to lay in bed for hours almost every day for 2 weeks. It's gone now.