My Feet Are Cold. Am I Crazy ?

Hello, I got a question... I never had problems with my feet being cold so when I got the same I really cant explain myself why. Winter came and its obviously colder in my flat maybe 2 degrees than normal, but my feet began to be ice cold, like, I wear 2 woolen pairs of socks granny made me and still no warmth, just when I go to sleep with those socks one and under the cushion my feet begin to get warm. Not all the times its like that, some days my feet are warm and in some not, I realised that maybe my change of lifelystyle from Active to Stative might have had some influence on it. When Im making physical excersizes I dont feel my feet are cold. Am I crazy? Also, can the problem of cold feet be related to my hypothyreosis, diagnosed quite recently (not cured yet)?? Thank you, Michael