Suggest Treatment For Headache Towards Back Of The Head

Hi, I have a throbbing headache towards the back of the head. i can cope ok with that part. The main problem is that is radiating all the way down my back and each step I take is painful. It is not sciatica as i have had that before. Light does not hurt. I vomitted yesterday and have slept most of yesterday and today so far. The pain started on Wednesday. I have taken paracetmol< had a hot bath but nothing is helping. Can you help me please?