I agree that a doctor is in order here, especially if you have a heart condition. Please don't gamble with your health. That little niggling issue that you notice & ignore can always turn out to be a symptom of something much worse.
That being said, two more things to add to twinieten's post: 1) I am always a bit more fatigued and require a bit more sleep when I'm in a calorie deficit. But just a bit, nothing extreme. 2) You posted quite recently that you're getting divorced and you've been very stressed. The stress would be enough to leave me fatigued, but I've also been through a few bouts of depression in the past, and I felt exactly like you do now in terms of the fatigue / sleeping forever.
to you. I hope that whatever it is, you feel better soon.