Hi I'm currently suffering from excessive daytime sleepiness. I sleep for 8 hours a night but still I feel sleepy throughout the day. I yawn like 120 times a day. If I close my eyes and just relax somewhere I fall asleep there immediately. I did all the necessary tests like thyroid, liver profile, kidney profile, cbc and all the test reports are normal. Expect low vitamin d levels for which I'm taking capsules. In the past 2 years I lost around 20kgs without even trying and now I've become very skinny. My hands and feet are always cold and I tend to feel cold as compared to other people. My resting heart rate is in the range of 55-70. Can anybody guide me as to what might be the reason for the above symptoms. I'm thinking of doing a cortisol test.