What you are describing here sounds like a severe headache; though unlikely, it could be also a sign of an aneurysm or hemorrhage. Like many other disease, however, you age and other medical problems make a diagnosis of hemorrhage/aneurysm more or less likely. If it is one of theses diseases, however, they are almost always accompanied by a loss of motor or mental functioning (i.e. you can't move one of the sides of your body, or you can talk appropriately). Regardless, if your pain is still continuing, you should call your doctor or go to the emergency room as soon as possible.
You are correct about birth control and smoking. They both increase the risk of getting a clot in one of your vessels.
So let's say your pain is not an aneurysm or hemorrhage in your brain, what is it, then? One, it could be a severe migraine headache. Migraine headaches are usually characterized by one-sided pain, nausea/vomiting, pain/avoidance of light and/or sound. Sufferers usually note a aura or feeling like a migraine headache is coming on. Also, migraine patients note a changes in vision, like flashing lights or changing colors before or during an attack. If you get several headaches like this at a time, and then not for months, only to get several at a time again, you could have cluster headaches. And I should definitely note that tension headaches - those brought on by severe stress in your life - could be causing your symptoms.
As I said before, only your doctor can tell the difference between these illnesses. Even if your pain is gone, for your piece of mind, make an appointment with him (or her) to figure out the cause of your headache. Be sure to note the timing, associated symptoms, and what makes your headache better and worse so you can discuss these with your doctor; these pieces of information are vital for making the right diagnosis!
To your health,