Welcome to HCM
The symptoms you have described as poor concentration, daydreaming, headaches
and problem of reading one thing again and again. While writing you have problem of mixing letters and you have to erase and write again.
It may occur due to dyslexia
but dyslexia is common in childhood and less common in high school.
It may occur because of mild form of depression
. Mild form of depression may present with poor concentration, poor performance in studies.
It may be a sign of early stages of OCD
. As you have problem of writing and erasing words, it may be a feature of OCD. But for definitive diagnosis detailed evaluation is needed.
I will advise you to please visit a good Psychiatrist
Dr. Seikhoo Bishnoi, MD