So this morning I was laying on my right side and when I went to turn on the other side I moved my…

So this morning I was laying on my right side and when I went to turn on the other side I moved my leg and felt and heard a loud pop down where my pelvic bone is .... I've already been having horrible pressure and pain down there like on a level from 1-10 I'd say it was about a 7 in pain but I know that is normal at 37 weeks but what about the pop I felt , what could that of possibly been ?