With respect, your co-workers could consider that you forcing a change in their shift pattern is exactly the same; one staff member holding all the power.
Perhaps the co-worker who is unable to accommodate you has a very valid reason for his stance. He will have himself and his family to consider in decisions he makes.
I have never worked shifts, and I know I would find it a horrible challenge, so I do feel for you in that regard.
I think Noblehead is suggesting that whilst your bloods might always rise when working nights, by utilising a pump and giving yourself a a different insulin delivery mechanism, you could see an improvement in the management of your bloods.
Would your clinic be able go give you a pump trial? Arranging and working with that would probably allow you more time to make your mind up and maybe even find another roles within the same company?