Pleases post your thyroid related test results and reference ranges shown on the lab report from 2 years ago. Also, same for recent tests. What symptoms did you have 2 years ago and what symptoms do you have now?
I really didn't provide any help, so I just wanted to mention that you should read about postpartum thyroiditis. I am also dubious about the first diagnosis of Graves', based on a "colorful" ultrasound, that then went away due to "diet and lifestyle changes".
At any rate, are you still taking the NatureThroid? Are you still having symptoms?
Can't even venture an opinion without knowing your test results and their reference ranges from before and after starting the med. Even more importantl what symptoms did you have before starting on the med?
Before I forget, the lab tests for T3 Uptake, Total T4, and Free Thyroxine Index are outdated and not very useful compared to Free T4 and Free T3. If it were me I would refuse to pay for those old labs in the future. Insist on Free T4 and Free T3.
Since your first, hyperthyroid set of lab results at 6 months postpartum, all the rest are indicative of being hypothyroid and in need of med increase; however, hypothyroidism is correctly defined as "insufficient T3 effect in tissue throughout the body, due to inadequate supply of, or response to, thyroid hormone". So it is not just the levels of thyroid hormone, but the effect of numerous other processes and variables that affect TISSUE T3 EFFECT. Some of the more important of these are cortisol, Vitamin D, B12 and ferritin.
And your August labs were not just slightly abnormal, but significantly low. When taking NDT, Free T4 is best around mid-range, with Free T3 in the upper part of its range. D should be at least 50 ng/mL, B12 in the upper end of its range, and ferritin should be at least 100.
Since there is no direct measure of TISSUE T3 EFFECT, indirect measures are required. The best indicator of thyroid status is signs/symptoms that occur more frequently with hypothyroidism than otherwise. These then are supported by expanded testing for Free T4 and Free T3, and the others I mentioned above.
Hypothyroid patients have reported having reactions to raising NDT or T3 meds due to low cortisol or low ferritin. Your stomach pain is not one I would normally relate to this issue, but it is the best idea I have at the moment, since it seemed to start with the increase in dosage. Before going further on that, do you have any other symptoms?
Yes, autoimmune disorder is called primary hypothyroidism. There is also central hypothyroidism, which is a dysfunction of the hypothalamus/pituitary system that results in TSH levels that are too low to adequately stimulate the thyroid gland to produce hormone. Most doctors seem to think that primary is the only type and that central is rare. Central is a rarity only because doctors typically only pay attention to TSH and overlook it. There are also various types of thyroiditis. You can also become hypothyroid due to diminishing Free T3 levels with age. Hypothyroidism is not just inadequate thyroid hormone. Instead it is correctly defined as insufficient T3 effect in tissue throughout the body due to inadequate supply of, or response to, thyroid hormone. So it is not just thyroid hormone levels, but it is also affected by many other processes and variables. If you want to read more about all this, click on my name and then scroll down to my Journal and read at least the one page Overview of a paper on Diagnosis and Treatment of Hypothyroidism: A Patient's Perspective. If you use the link to the paper, note on page 7 the diagram of the main parts of the thyroid system and you will see it is much more involved than just a test for TSH.
If you cannot absorb Vitamin D, or other, you can ask your doctor for weekly injections.
I would push to have the antibodies done again. TPO, TG and TSI. When was the last time your doctor checked your antibodies?