True story: I have a vitamin D deficiency and am taking a weekly dose of it each Sunday. >_>
How big is the dose?
I absolutely have to ad here that a vitamin D deficit was the main reason for my panik attacks. Other hormones where probably going rampage too but most of my problems just stoped when taking the pills.
It is just called a vitamin making it sound more harmless than it is, it actually acts as a steroid.
Symthoms are very subtle at first, it attacks the mind making you nervous and short tempered all the time, way before physical problems appear.
Physical symthoms start with very short stinging pains eg in the neck or legs. Generally when a bone has to deal with pressure, at that point you bones start to get damage because the balance between the bone disolving parathyroid hormone and the activated form of vitamin D is disturbed.
Next you end up with calcaemia, the body tries to repair the bones, gathers calcium in the blood but fails to build it in so it damages your nerves.
Your cholesterol levels will rise too, if your doc ever said "Your colesterol is high" then stop trying to eat healthy and get you damn vitamin D levels checked.
Also: yawning, gosh you will yawn so hard, a dentist could give you a root threatment without that you even notice.
For reference: i was prescribed 20.000IE per day. If you think now you can go to a drugstore and get a pack of daily eaten vitamin pills to counter a theoretical deficit then remeber you have to eat the whole pack at once to get the result of real medicine.