I'm sorry, I don't know!! But I wanted to wish you all the very best for this morning - hopefully your midwife can help you get more comfortable.
If your bub is posterior, you are doing the right thing with the positioning, I believe. I was told to kneel and lean forward against something, keeping your legs comfortably apart, so keeping your pelvis open.
When in labour I found straddling a chair and leaning forward against the backrest comfy for me.