I am confused indeed..
My understanding is that if the thyroid is removed, then you have to have thyroxin replacement therapy similar to myself that has an underactive thyroid! so don't understand how vit d can be prescribed as a replacement thyroid...
If you've got an underactive thyroid, this can hamper BG control..
I can't say if excess calcium levels play any part in control..
But as you said that your problemtic readings have happened in the last 4 days, perhaps it's the infection causing higher reading which is normal reaction, so you may need to increase your insulin, until your antibolotics kick in and the infection subsides, but you will need to monitor your BG, keep a good supply of what ever you use as your hypo treatment, just in case the when the infection subsides and causing a very quick drop in your BG levels..