Could you please tell us the reference range for the Free T4? Ranges vary from lab to lab and have to come from your own report. There is no Free T3 result, and Free T3 is the most important hormone as it's the one that's used by individual cells in the body. Can you get this test done?
I'm not familiar with melanxit, but a bit of research indicates that it might be an antidepressant. Is that correct? If not, please tell me what it's used for. Many doctors find it much easier to prescribe an antidepressant than to simply deal with the patient's symptoms...
That said, it's highly unlikely that you'd get symptoms like that from a single dose of Thyronorm, especially only 25 mcg as it's a very low dose and it takes 406 weeks for it reach full potential in your system; however, it's not unusual for symptoms to worsen or for new ones to appear once one starts on thyroid hormones because the body has to get used to having the hormones it's been doing without.
Like most medications, any side effects typically go away once the body gets used to the medication.
Rarely, people react to fillers, binders or dyes in the pills and have to try pills from a different manufacturer. In the U.S. the 50 mcg pills have no dye (they're white), so many do okay on those, but not on other dosages. If yours are that way, you could try splitting 50 mcg pills to get the 25 mcg. One day you could take half of a 50 mcg pill to get 25 mcg, the next day you could take a whole 50 mcg pill, the next day take the other half of the 50 mcg pill for 25 mcg again... and see if that helps.