Hypothyroid. Is it used to treat for?

Hello, I have diagnosed with thyroid three years back and stopped the medicines after 1nd half year, now I have been facing lot of issues like chest pain, sharp pain in the chest sometimes... My calfs pain hard I couldn't be able to sleep at night, my left arm pain sometimes.. I have been suffering from anxiety and suddenly without any reason my beats so fast... Few days back I consulted an endocrine and got the tests done, my tsh level was 6.65.. and calcium was also less... He gave me tablet electroxin 25 ( I don't remember the name exactly) and benfolace tablet .. I don't know what is the benefit of it... And 60k vitamin d - sachet that I have to use weekly once.. I forgot about the benfolace intake, can anyone help me with that how to use it and what is it used to treat for? Also, have I prescribed with the right medicines according to the condition.