I am very sorry to read your post, understanding how you feel well.
I had a healthy life until 2017, when all of a sudden I had troubles with sleeping. After treatment with psychiatrists, I finally got the right diagnosis: epilepsy. It is known that epilepsy affects one's sleep. With my treatment for epilepsy, my sleep has been improving. But as I have already shared in another post within this group, something that has helped me much in difficult times was Yoga Nidra, also known as yoga sleep. Scientific studies on this yoga practice have shown that 30 minutes of yoga nidra can correspond up to 3 hours of deep sleep. This is what has given me much strength at those difficult times. I practice yoga nidra from the Insight Timer App, but you can also find some practices from Swami Satyananda (father of the modern yoga nidra) on YouTube, such as this one: https://www.youtube.com/watch
Don't give up. All the best to you!
Santosha