I know what you mean, I have to sit on my hands in order to avoid over-candling my quail's eggs! Nothing is more exciting to me than hatching eggs. I would do it for a living if I could!
In the photo you showed that's not a bullseye! Just a nucleus called a blastodisc. The bullseye, called a blastoderm, looks similar to that but is much more than a little white spot! It will be twice that size and look like a white ring AROUND a spot, and usually with some beginnings of veins...
Sometimes if your candling light is too bright, it will shine right through very fine veins or a tiny embryo! It can also be hard to see through spotted, thick shelled, or dark coloured eggs.
Well, after 5 days there won't be much change, but from the picture you've posted that ''bullseye'' spot is just the hen's contribution toward making a chick called the nucleus; seeing that doesn't necessarily mean it's fertile. What you want to be looking for after about a week is a spiderlike...