When making considerable changes to our diet (especially cutting-out refined Sugar and processed foods), I believe it's quite natural to feel lousy for a few days. This could be die-off, or simply your body attempting to adapt to different foods.
It's great that both yourself and your husband are following the diet together as it means you can support each other through the tough times. Be loving and patient - it's important to allow your body time to heal...don't rush too much - and you'll get through it!