I am glad you're feeling so much better. I assume you have an Autoimmune Thyroid Disease also called Hashimoto's as you had/have antibodies. Some doctors don't prescribe levothyroxine due to the TSH level being low, but Dr Toft of The British Thyroid Association recommends levothyroxine if we have antibodies. This is also an excerpt from Thyroiduk.org.uk:
"The Myth that Thyroid Auto-immune Antibodies never hurt anybody"
Patients are frequently told by their medical practitioners that their thyroid antibodies are not harming them. However, the most common cause of hypothyroidism is, as you probably already know, Hashimoto's disease. Now, in Hashimoto's disease thyroid auto-immune antibodies attack and destroy the thyroid hormone producing cells in your thyroid gland. Such attacks may initially stimulate the thyroid into over activity but the auto immune antibodies gradually turn the thyroid into scar tissue, destroying in the process its ability to produce thyroid hormones. I'm not sure exactly what triggers all this off but it comes to mind that since cortisol, one of the adrenal hormones, actually moderates the immune system, one predisposing factor in this might perhaps be the presence of adrenal insufficiency.
In reality you should not have any autoimmune antibodies in your body at all although of course you do need normal antibodies to provide you with vital resistance to infectious diseases, etc. If you do have autoimmune antibodies, you can be sure that they will be doing you no good. Furthermore, if you have one type of autoimmune antibody active in your body, you may well have others to go with them, and they won't be doing you any good either.
This is an excerpt from Dr Toft's article (he was President of the BTA.
2 I often see patients who have an elevated TSH but normal T4. How should I be managing them?
The combination of a normal serum T4 and raised serum TSH is known as subclinical hypothyroidism. If measured, serum T3 will also be normal. Repeat the thyroid function tests in two or three months in case the abnormality represents a resolving thyroiditis.2
But if it persists then antibodies to thyroid peroxidase should be measured. If these are positive – indicative of underlying autoimmune thyroid disease – the patient should be considered to have the mildest form of hypothyroidism.
In the absence of symptoms some would simply recommend annual thyroid function tests until serum TSH is over 10mU/l or symptoms such as tiredness and weight gain develop. But a more pragmatic approach is to recognise that the thyroid failure is likely to become worse and try to nip things in the bud rather than risk loss to follow-up.
Treatment should be started with levothyroxine in a dose sufficient to restore serum TSH to the lower part of its reference range. Levothyroxine in a dose of 75-100µg daily will usually be enough.