Headache right before orgasm????

For the last week I have been getting a huge headache right before I have an orgasm and then I have a headache the rest of the day. I started my period yesterday so I don't know if that has something to do with it. It's never happened before now. Also, what can I do to relieve the headache? I don't usually get headaches that last more than an hour and these last a day at least.