6yo severely constipated

Dd is 6. She is severely constipated and has been for 6 months. We have done a total cleanout 3x now and she takes Miralax daily. We began Miralax 5x a day and Dulcolax 2x a day on Tuesdy and nothing. Her belly is hard and she just is miserable. She has lost feeling in her rectum due to it being stretched and she poops herself at minimum 4 times a day. She cant control it. Poor thing is so embarrassed.The doctor said our next step is to insert a NG Tube and flush her out. It will be done in the hospital. From my understanding she will be awake as they insert it. I don't want her to be scared or in any more pain.Is this our next step? Anyone been there, done that? I hate to see her in pain but we are at the end of our rope.
The doctor even used the word Obstipation. I guess it is worse than plain constipation.