i can relate to severe headaches as i have suffered with migraines for many years...i agree with el dave that a visit to your doc is a good idea.
have you been under any stress lately? added stress can be a cause for both the headaches and missed periods. if you have a gyn doc, would be a good idea to schedule visit with him/her as well...don't be embarrassed...it's something you need to have checked out. hope you feel better! let us know how you are
Well, was that study period you skipped, lunch period, what? No, I'm sorry.. obviously I wouldn't know too much about that part, but I can tell you that the headaches business doesn't mean a brain tumor, despite your grandmother's unfortunate experience. A great great many folks get headaches, sometimes monstrous ones, and only the tiniest little percentage turn out to be something like that. Don't stress over that, it'll just make it worse. Perhaps you might consider going to see some doctor, though, get a checkup, set your mind at ease, get those headaches toned down and hopefully completely out. As for the other thing... uh... (Ladies? Ladies? Any ladies here care to step in and rescue me here?)
-El Dave