What the previous poster means, is that the weekly mission isn't explained properly.

How weekly missions work:

1) A maximum of 5 Weekly missions can be done in a week. Once you done 5, you cannot do more.
2) There are usually more than 5 to choose from.
3) The Special Weekly missions at the top gives more than the bottom ones, so do those first.

Don't worry, next time just ask here instead of reading it or blame yourself. :lol