Thyroid condition does come to mind, however, that's been almost ruled out (my sister does have nodules, too, however, she is on thyroid med's). Did you get a complete blood work panel done to make sure everything else is at the level it should be???
Have you taken any sleep tests??? You could have sleep apnea. It's amazing how many people have it and are unaware. Your doctor's office may give you a simple, home diagnostic test that will give you preliminary results. (i.e. when you are ready to go to bed, you attach the finger device and go to sleep as you normally would. Then, return the device to their office the next day, for an evaluation.) If you do not pass the test, they will refer you to a sleep specialist who will have you evaluated at a facility, overnight (i.e. sleep study). If you have any kind of allergies/asthma breathing or heart conditions, or if you know you are a snorer or awake suddenly in the middle of the night for no good reason,
you could have some sleep apnea. Foggy thoughts, weight gain, severe fatigue are all symptoms of it. As far are the other symptoms like your hair - could be just the season or you could be lacking some kind of vitamin in your diet.
Are you taking a good multi-vitamin? During this time of year, we all are getting lower doses of Vitamin D and recently, there have been so many studies out about the benefit of Vitamin D3 (even working in conjunction with Vitamin C)
Don't rule out the physical aspect of raising twin girls. That has to be a constant, physical challenge and I'm sure you are in constant motion. And it would be natural for your libido to be lacking if you are that tired.
Back to the sleep test - It's the road I am taking now. My dr. mentioned that she wanted me to take a home test and I told her it wasn't necessary. Flash forward - I have failed two home tests and it's been enlightening. Looking back, I may have had sleep apnea for years without knowing. Good luck.