Eather 3ds is broke or my vision wont let me see it?

ok so i've had my 3ds since the launch date but just recently when i started to play ocarina of time I can still see the 3d but every once and a while the left eye and right eye image will sometimes overlap the image and will make it extremely annoying to play, i asked my cousin and sister if they saw the same thing and they said no so it might just be my vision. does anyone know if it is, and if it is, is their any eye exercises or contact lenses that will help me?