HELP! Sudden, severe pain in tailbone

I am 16.5 weeks pregnant and really popped this past week. Over the past month I have been getting bad tailbone pain, alleviated by rest and stretching.

Today I noticed the pain when I was grocery shopping, came home and worked on a sewing project (cross-legged on the floor...I guess not a good idea!) And got up and had some bad tailbone pain. My husband tried to rub my back a little, but when he put too much pressure all of a sudden I was in excruciating pain and screaming! It feels like it is popped out of place or something! Now I have extremely limited range of motion, shooting pains, and severe pain. I am trying to stretch and twist hoping this pain will go away and it will pop back to a comfortable place, but even the most subtle movement is very painful. Especially an arch of the back. Any tips? Please help. I am not sure if I am being a baby or if there really is something wrong!