Well, it sounds vascular to me. It's like you're having a migraine without the migraine. A migraine happens when, following a period of stress that constricts the blood vessels, they open up. Because the larger vessels open up more quickly than the smaller ones at the extremities blood rushes to the head. So if your head is warm and your hands and feet are cold, it sounds like your blood vessels are constricted at the extremities and therefore the blood is rushing to the wide open vessels in the head. Don't know how you can test this if you're not actually getting the other symptoms of a migraine, but something you can try is biofeedback or meditation or exercise that evens out the blood flow, techniques that help with migraines, and see if it mitigates the problem. Otherwise, no clue.