I feel cold and very tired, especially in the afternoon. sometimes I go into a really deep snooze which is so not like me! I am 65 and female but am normally very active: I go to the gym three times a week and also do zumba and aquafit once a week. I had a test for thyroid which came back as underactive but my doctor asked me to wait for another test in 6 weeks which I did but that was normal. Any ideas?