Ideally you'll have both sunglasses and goggles. You'll need goggles with a tinted lens for when it's cloudy and there is 'flat' light. Alternatively get goggles with interchangable lenses (v. expensive).
I have sensitive eyes too and use some Adidas sunglasses actually made by the people that did the visors for the Apollo spacesuits. The lens is called Space and cuts out 95% light. Try to get a frame that wraps around your face so that there's little if any light creeping in at the sides of the glasses.