Headache!

Recent two days a series headache bothered me! I have not found out the cause. Maybe it is from a caffeinism. Last Friday morning I drunk a cap of green tea bought from 7-11. In my experience that would be okay if I drink tea in the morning. The caffeine only affects my sleeping until midnight. I forgot the caffeineism will bring a headache symptom after I stop drink coffine. Headache let me weak. Hope this headache would be disappeared as soon as possible.