the nausea doesn't last long....only a few days....the girls around here recommend fiber (in the form of beans and high fiber veggies) to help....also lots and lots of water.
For most people it doesn't last more than 2-3 days.
Also, make sure to eat enough....if you aren't getting enough calories, your hunger might cause nausea.
The nausea is a byproduct of your body "flushing" out those bad carbs and sugars that your body has become so accustomed to. Think of yourself as a recovering crack addict