What Causes Headache?

hello im a 16 yr old student and this is my porb iv latly ben feeling like im slow and sleepy my eyes hurt and a get headaches a few times a day i think iv got a cold and i thing it might be messing with my haed a bit cos of the fact that i get worried about some things and then when i know that its dumb to think of things like that i some thins thinks that im going crazy i know im not but it still gets to me what is wrong with me and what can i do to fix this