Hyperparathyroidism is one of several endocrine disorders that could explain your symptoms. Also possible is a food allergy/sensitivity, perhaps from something that sneaks in as an ingredient in prepared foods you eat.
To correct a few points in Bama_Lori's otherwise useful info, eggs are not a good source of calcium or vitamin D. And if you have reactive hypoglycemia, orange juice is not going to be useful. There are very few foods that have a significant amount of vitamin D; the best way to get the "sunshine vitamin" is through sun exposure or a supplement (D3 form is preferable). Calcium can be found in a variety of leafy green vegetables, as well as some nuts, but not in large quantities. If Ca deficiency is identified as a problem, talk to the doctor(s) involved about supplementing.
Last, I'm not sure that eating every two hours is ideal for reactive hypoglycemia. Again, check with the doctor(s) treating you to see if altering what you eat and when you eat it might help you feel better.
PS...if it is HPTH, then adding the calcium wll help you feel so much better in every aspect.
When the parathyroid goes wrong, it commands a high level of calcium in the blood...so if you dont eat it, it pulls it from the bones....then bone calcuim clogs the kidneys causing stones and flank pain...so if this is it...this could be causing all of that...plus excruciating pain and fatigue. Add the calcium dietary if you can and are not allergic to it, worth a shot...
Dan Active is the best I have found for all my stomach ills and adding enough calcium in a quick four ounce shot. Eggs are good for calcium and D. Orange juice with added calcium is good too.
Look at Hyperparathyroidism...this is not checked with thyoid tests and rarely will docs put it all together before sending you round the gammit and back.
Good Sites for this: Endocrine Web and Parathyroid.com If they are thinking adrenal...the parathyroid is also an endocrine gland...just like adrenal is.
This will cause your metal counts to be off as well, but primary things to look at are
Calcium Level...
Look at the symptoms for hypercalcimia High calcium
and PTH level
Parathyroid hormone...they will not check this less you ask for it....trust me, they never think of that.
And low vitamin D symptoms
High calcium will cause low D.
Hope this helps and get well soon!
Lori