Hashimotos is a type of hypothyroidism
. This means that your thyroid is not working properly. The thyroid causes increased energy in the body. So the lethargy
that you face is because of you underactive thyroid. If you have a low vitamin D that means that you could have some other pathology or just low diet intake. One easy way to increase vitamin D is to go out into the sun.
The sun converts cholesterol
to vitamin D and is useful for getting vitamin D. I hope this helps.