Going away from home for a few weeks is not a problem. The worms
will simply continue eating the garbage left in the bin. Eventually
their food supply will decline enough that the population will drop.
This will remedy itself as soon as you begin feeding the bin again.
If a month or more is going to pass without adding food or if the
house will be unheated during a winter "sabbatical," you should give
your worms to a friend to care for.