Does anyone have really bad pelvic instability (pains and discomfort when walking, sitting, lying)

This is my second pregnancy.  I'm a dance teacher and my first pregnancy was smooth sailing. I danced and taught the entire way through it and apart from feeling heavier and generally pregnant.  This time has been terrible however. My sciatica is Unbareable and I can barely lift my right leg off the floor. I feel like I have been kicked in my vaginal region by a horse several times and getting up to walk after sitting or lying is so painful. Not to mention trying to change positions in my siting or lying times.