It’s possible that you have what is called delayed phase sleep disorder, although I’m not sure it really is a disorder except socially. Some people are just genetically wired to be night owls, and there really isn’t any way to change it. It’s not a character defect, or insomnia. I’ve struggled with this my whole life. People don’t understand, and they keep suggesting the same old things that I already know don’t work.

It’s hard to fit into the world with this kind of difference, but if you can rework your schedule, you will probably feel better. My sympathies, I know firsthand what it’s like.

Mrs Bradshaw’s Handbook, by Terry Pratchett comes to mind, although I suspect you aren’t looking for a book about a train journey through an imaginary landscape.