What Causes Headaches, Vision Trouble And Nosebleeds?

Over the past year I have began having headaches accompanied with vision trouble. I work with computers a lot and just chalked it up to strain or weather. Over the past two weeks the headaches have been pretty strong and I have had nosebleeds. ( I have NEVER had nosebleeds) The weird thing is the bleeds come first followed by the headache. I was woke last night with one at 2:30am