Today I experienced sudden onset of servere throbbing pain in the back of my head near the top of my neck, completely out of the blue. I do have a stressful job, but was on a day off and often get headaches due to probable dehydration, but this lasted for a good 3 hours or so. The pain made my neck feel stiff, my eyes want to stay shut, was not relieved at all in any position and made me feel sick and cold. Now that it has passed I just feel very tired. My GP made me go to A@E for a head ct but I had to wait and the pain subsided so I decided to go home. Should I be worried or could I put this down to dehydration or stress?? My blood pressure at the time was unusually high for me, at 156 and I had no temperature. Thanks