How severe is the weight gain? Quite a few medical websites state weight gain from hypothyroidism is usually around 5 -10 pounds (2.2 - 4.5kg). That said, i found a study, reported in the journal Clinical Endocrinology, with the following results:
"Overall, among the entire group, at the end up one year, weight was up by 3.95 (kg 8 3/4 pounds), to 9.91 kg (22 pounds) after 4 years, with a mean weight gain of approximately 3.66 kg (8 pounds) per year." - Dale, J., Daykin, J., Holder, R., Sheppard, M. C. & Franklyn, J. A. "Weight gain following treatment of hyperthyroidism," Clinical Endocrinology , 55 (2), 233-239.
Other medical conditions that cause cause unexplained weight gain include Cushing's Syndrome, ovarian cyst/s, PCOS, insulin resistance.
High serum folate levels can be caused by excess folate in the diet, autoimmune pernicious anaemia or blind loop syndrome. Check for thyroid antibodies (TPOAb and TgAb) as well which can cause hypothyroid symptoms regardless of other normal thyroid results.
Your T4 test is actually Free T4, which is very different from Total T4. The result is okay. Your T3 test is Total T3, which is somewhat outdated and not nearly as revealing as it would be if it were a Free T3 test. The difference between Total and Free is that most thyroid hormone is bound up with protein molecules and thereby inactive. Only the unbound, or Free, portion is biologically active.
You really need to get tested for FreeT3, along with Free T4 and TSH. While you are at it, I would also suggest that you be tested for Reverse T3 as well. Reverse T3 is the mirror image molecule of T3. Under some conditions the body will convert T4 to excessive amounts of Reverse T3, which counteracts the effects of Free T3 and produces hypothyroidism. This does not happen very often, but with your symptoms and your prior test results, I would have it checked out.
Since many hypo patients also are deficient in other areas as well, I wold suggest that you also get tested for Vitamin A, D, B12, iron/ferritin, zinc, selenium, and RBC magnesium.
When test results are available, please get a copy of the lab report and post test results and their reference ranges and members will be glad to help interpret and advise further.
My symptoms are hypothyroid and yes I do have all of them plus sever leg, foot and hand cramps. Along with that not modest weight gain but sever weight gain over several years.
Sorry, somehow I didn't get the link posted. Here it is.
http://endocrine-system.emedtv.com/hypothyroidism/hypothyroidism-symptoms-and-signs.html
When you say that you have all the symptoms, are you talking bout hypo symptoms? If so, of the 26 hypo symptoms listed in this link, how many would you say that you have?