What Causes Persistent Headache All Through The Day?

iv been ill for nearly 3 weeks now im 17 years old iv been suffering from headaches i get then all day from when i walk up in the mornings to when i go to bed at night i also have been really shaky, feeling sick, lightheaded and feeling all spaced out like im not even here iv been to the doctors and they gave my tablets but there not working iv tried everything to get rid of my headaches hoping everything eals would go with it, iv tried wearing my glasses, going to bed early, 4head, cool strips, drinking plenty of water, fresh air, different pain killers, migraine tablets but nothings work please help me