Some people have high serum calcium. It may be due to the way they process it. Or it might indicate bone tear-down because you are not absorbing enough from food due to low D.

The parathyroid gets involved here, and this gets complex. I don't really understand it all myself, but some people have a condition called Paget's.

Here is an article about high calcium in the blood.
Paget's is #7 listed. People with Paget's also have elevated alkaline phosphatase enzyme levels (liver tests).
http://www.parathyroid.com/high-calcium.htm
I don't agree that it is so "rare"... And I don't agree with the high Vit D intake...that has not shown to be very common in recent studies, but was cited in the "old days" along with warnings about D and hypercalcemia.

It can get quite complex, so don't over worry yet.
I am reminded of a show I saw recently Dr. G (the Science
channel's autopsy show)... she did a post on a 55 yr old woman who suddenly died, and found the Paget's in the skull when she took the skull off. But there were no other signs of it and Dr. G said that is what sometimes happens. The Paget's can be mostly silent, and rarely if ever results in death. (the woman died of alcohol abuse and diabetes).

If you fix the D levels, then have the calcium redone, you'll know more.
You'll also want adequate levels of magnesium as this mineral helps get calcium into the bones. Low magnesium would impair bone building in general.

The heart needs calcium to work, and so do the nerves. So when calcium is low, the body tears down bones to provide it.
(low D would reduce absorption from food and supplements as well from the GI tract).

And certainly all of us would be pleased to have you continue posting here your experiences and progress. We all help each other this way.