Reasons for middle of night awakenings (wide awake, no anxiety, takes 1-3 hrs to be drowsy again) besides obvious ones such as mental health issues, pain, noise, hot flashes, etc.

Most likely: Menopause. Your age mentioned in your health information goes in favor of this possibility. I hope this is helpful. Please check up with your doc. Best wishes for you to feel better soon.

Sometimes: Levothyroxine can sometimes contribute to insomnia. Have you checked sleep hygiene? Are you drinking alcohol before going to bed? Eating late? Exercising during the day? Smoking? Is the room temperature comfortable? Ambient noise at a reasonable level? Any issues you may be ruminating on while you sleep? The "z" sleep meds and melatonin can help on a short term basis. Good luck!

Insomnia: Well i would rule out sleep apnea and do a sleep study and rule out medical causes also before assuming its just menopause.

Awakening: There are many reasons for middle of the night awakening . I just wanted to add one more to the list. Many people think drinking a little wine at night might help them sleep, in fact, they may fall asleep, but there is a rebound effect that causes the person to wake up in the middle if the night. So, avoid alcohol if you have sleeping issues!