Ask an Eye Doctor and Get an Answer ASAP
Strokes usually do not cause headaches. Your symptoms of sudden vision loss with headache is very concerning. What is your age? What other medical conditions do you have? How bad is the vision loss? Complete? Was there any flashing lights? Is the eye itself red or painful?
The loss of peripheral vision in both eyes does point towards a TIA or stroke. There is no treatment for strokes that has already occurred. However, I would at least start you on Aspirin (and you may need to be on Plavix or Lovenox). I would also get a carotid ultrasound to look for the source of the stroke. The point is to try to prevent a larger event that can affect a larger part of your brain.
You need to be seen by an Ophthalmologist and get a visual fields test to determine if indeed it is a stroke. There are other conditions, like temporal arteritis (usually just affects one eye) or retinal detachment that needs to be ruled out.
Hope this helps.