Calm down. Rapid weight loss often happens in a whoosh like this when you first start out. It is mostly water weight. This will slow down soon and will not hurt you at all. You do, however, need to be sure to get enough salt in your diet as your body gets used to this new way.
A good way to do this is mineral water with a little lemon or lime juice and some salt added. Primal gatorade.
I wish you well.