Really weird headaches?!

For about 2 days now I have been getting these weird headaches. There only seems to be pain when I do anything that causes blood to rush to my head. For example, coughing, sneezing, even when I am just sitting still, if I slightly tilt my head down to look at the floor, it's EXCRUCIATING pain. I can't even bend over to tie my shoes....that is the worst! Even taking a deep breath sometimes is so painful. If I sit perfectly still and look straight ahead there is usually no pain, but the second I move my head, or especially if I attempt to get up, it feels like I am being hit on top of the skull with a brick. This happens for 3-5 days about every year or two to me, and the doctors can't seem to classify it.