Have your doctor check your Vitamin D levels. Mine was so low and I was tired and depressed. Once I started taking the high dose prescription of Vitamin D3 I started feeling much better.

Go see the doctor about getting a referral to a Sleep Clinic. He will set this up for you & you will go there over night for a sleep test where they hook you up to a machine & monitor your sleep. The doctor will check your readings & let you know if it’s Sleep Apnea. Please have this done because it sure sounds like that is what it is. Sleep Apnea is like when your brain is not getting enough oxygen when you sleep. Nasal passages close up so no air can pass. Air is obstructed. Do yourself a favour and have Sleep Apnea checked out.

are you watching what you eat, and how you eat it? Low blood sugar levels can cause a "crash" of low energy!

Sounds like Sleep Apnea. Have that checked out. Have you ever been told that you snore? I had know idea that I had this problem. Many people take Melatonin to help them sleep. My grandson who is only 7 takes this so he can get a good nights sleep. Sleep is so important!

I have been having the same issues. I am tracking my sugars when I am tired to see if high blood sugars are in part the issue. See if it is a specific time of the day this happens. I am trying going for a brisk walk before driving. I have also found that just being still does the same thing. Check your sugars and keep a journal. Share that with your doc at your next visit. We have to be our own investigators so that we can present a complete picture to the doc when we discuss these issues.