I don't sleep since starting menopause (over now but still can't sleep). I have tried every remedy but as soon as I fall asleep I wake up suddenly and then can't get back off. I am now resistant to prescription meds too. I put on headphones, lie very still and listen to Audible books. No light to contend with. (Pick comfy headphones - splash out.) I listen to something light and preferably something to which I am familiar so I don't have to concentrate. I either fall asleep dreaming about the book (pick a nice one to avoid the dreams), or I stay awake until 4 or 5 in the morning and enjoy a good book! Win win. The secret is to decide that it doesn't matter. Then it doesn't. (I used to get up but I would be wiped the next day.)
To lead a tranquil life, mind your own business and work with your hands.
One more quick thing to add to this looooong and helpful conversation...try listening to a book with earphones (the flatter the better so that you can lay down your head). You can download free public domain works at librivox.org to an MP3 player and listen with the volume turned down low. If you miss some of the content when you doze off, you can always dial back and pick it up later. Victorian novels seem to do the trick for me, but everyone's different. Some of the volunteer readers' voices are more soothing than others. You can check them out before downloading.
Have you tested your progesterone levels? Progesterone, otherwise known as the sleep hormone, decreases with menopause. I take one drop of chasteberry tincture at night and sleep like a baby. You should be taking some oestrogen supplement too, red clover tea has been recommended already, it works well for me. You get this in combination tablets but pays to try many brands because quality varies widely.
You can never go wrong with yoga and meditation.
You should at least go see a therapist about those consistent nightmares. Sounds like your subconscious is trying to tell you something.