If you have a packed week? "packed week"是什麼意思呢?

It means you are lucky to have a packed one week holidays.
pack up=get ready for a journey by doing the packed up of your things.
You managed to pack a lot of sightseeing in eg:-S.E.Asia into the short time of one week you'll have in official holidays.
A package week holidays means a detailed plan holiday-tour with many details arranged by travel agents for a dream place holiday for a week in a package.

A packed week = a week that is full of tasks = a busy week.