Oh my gosh I have the same problem! Well, actually, for some reason, for the past year or so, my right eyelid has a double one now instead of a single one (which ive had all my life) i don't understand why?! just like ginger9 when i cry or sleep funny the stupid single eyelid comes back but then after a few days would go away. Sometimes if this happens and i rub my eye(which can't really be that good for the skin lol) it goes to a double.
So frustrating, i understand what you're going through! But to be fair, none of my friends really noticed untill i said so. you look lovely anyway without falsies, but they do look fab! What I do when my eye goes single, is to put a shadow like 'shroom' over the eyelid area on both eyes, and use a natural darker shadow(i use a bronzer lol) on the outer corner, to kind of create a crease, and match both eyes up. Sorry that's not very clear but thought it might help
x