I Have Been On Epilim Chronic For 13 Years With

I have been on Epilim chronic for 13 years with increased doses ending in 2000mg daily. I have had no tonic clinic seizures since 2012 but have become increasingly angry and dare I say pretty bi polar in nature. I have halfed my meds and taken only 1000mg since last month, since then I have had chest pains, anxiety. I have become shaky, have had diarrhoea daily, headaches and complete loss of appetite. My hair is falling out too. I am so confused! (I also have hashimotos disease) please help my Gp is no help