Just curious, is your diet unusual in any way (e.g. vegetarian, vegan, etc.), or was it otherwise unusual when you were supplementing vitamin D? I've never heard of hypercalcemia, but I have heard of osteoporosis, which I assume is caused by hypocalcemia. I have heard a compelling argument that a high animal protein diet causes osteoporosis because protein makes blood ph more acidic and the body draws upon its bone calcium to bring the ph back to normal. If true, it is scary that so many people are into protein supplementation and high protein diets (Atkins, etc.). I'm wondering if low animal protein could cause the opposite effect, and if animal protein may help hypercalcemia.
No. Pretty normal diet. It's often genetic and usually related to thyroid issues (which runs in my family, but so far I don't seem to have, at least nothing out of normal so far).
My treatment was to avoid vitamin D and calcium as much as possible until my blood levels return to a normal range, then reintroduce them slowly. It's harder than you think, since it seems like everything from orange juice to muffins these days is extra fortified to combat osteoporosis and to help with child development (Vitamin D and Calcium fortification in food stuffs is usually to prevent rickets but has the nice side benefit of supposedly helping with Osteoporosis later in life).
After a couple months the issues with the nerves in my face mostly went away and as that happened most of the fatigue disappeared. I'm unusually achy though, all over.
I can eat normal these days most of the time, but if I start feeling like I want to lie down and go to sleep all the time, or the muscles around my eyes feel twitchy, I usually just make sure to cut out dairy and stay out of the sun for a week or two and it goes away. Before I go to the beach or for some kind of extended outdoor activity I'll cut my calcium intake as well.
I usually come back from a day in the sun with skull shattering headaches though (which is supposed to be a sign of Magnesium Deficiency, but I test fine for that) so I don't enjoy many outdoor activities.