Headaches

I've been experiencing some headaches lately. I'd say about half of the days since school started, I've come home with a really bad headache, which has kind of wiped me out for the evening and made it impossible to get anything done (I often have some kind of schoolwork or planning that I do in the evening, or just stuff of my own that I'd like to do at home). I have long had a tendency to get sinus headaches, especially in the fall and spring, though I really haven't been bothered much by them for a couple years. Lately, they seem to have returned. Tonight, for example, I started to get one around 3:30 or 4:00 after school had ended, but just before I left for home. By the time I was home and had watched Jeopardy, my head was really pounding, so I took about a 30-45-minute nap on the couch. It wasn't a whole lot better when I got up, but now -- about two hours later -- it has pretty much gone away. It's just distressing 'cause I feel like I'm spending a lot of time not being able to get anything done.