Your suffering from headache that lasts for a week may be due to the following reasons:
Dehydration and a decrease in the amount of water in the body, which means a decrease in blood pressure, and thus the amount of oxygen that reaches the brain becomes less
Having anemia
Persistent headache is a symptom of various chronic diseases such as diabetes and alopecia.
Getting a lot of caffeine.
Suffering from sinus problems
Brain tumor