Seen an optician lately? You should see a doctor after that. Take care of yourself.

Your question intrigued me so much that i searched for books on Amazon dealing with "Headache" and to my surprise, there is a whole lot. You might want to try a couple; the book Splitting: The inside story on Headaches by Amanda Ellison (https://www.durham.ac.uk/staff/amanda-ellison/) seems promising.

Not a book, but I've had recent success with eating a diet high in omega 3 and low in omega 6.