Dear Vijay Kr Vishwakarma,
Dizziness, easy fatiguability, hypothermia, nausea, overweight/obesity are symptoms of hypothyroidism.
Apart from this, nutritional deficiencies can also be the cause.
You will also need high protein, nutritious diet.
I can only say this from the details you have provided.
I would suggest you to get thyroid profile tests done and follow up an endocrinologist elsewhere.
I wish to hear back from you, if you have got the thyroid hormones tested.

Dear Vijay Kr Vishwakarma,
Before proceeding further, I would like to state that, blood pressure of 90/60mmHg and 95 deg F are just within normal limits.
Hence you may not exactly be hypotensive or have hypothermia.

The following may be the cause for your symptoms
1. Endocrinopathies - Thyroid hormone are the commonest. Endocrine functions including adrenal hormones have to be checked.
2. Nutrition and hydration - Vitamin deficiencies in gross, other nutritional defiiciencies and not drinking good amount of water are the other factors.
3. Stress, occupation and psychological factors including depressions.

You could have included your age, occupation, or any other medical problems that you have in your reply.

Since thyroid profile was normal, you will need other endocrine hormone assessment, that include blood sugar, serum cortisol, ACTH levels checked.

Hence my suggestions are consider lifestyle changes. Increase fluid consumption and modify dietary supplements. More clear opinion can be suggested if all the endocrine abnormalities are ruled out. Hence, it may be necessary that you get blood work up as suggested by an endocrinologist.

Let us know the results of the endocrinologist work up. Get back if there are any queries.