You probably are in ketosis and the weight loss is another indicator. While you are losing weight then you will be losing water (glycogen is glucose +water so losing it increases fluid loss. You may lose electrolytes, so the advice is that whjile in the weightloss stage to increase salt intake. Also when in full keto you will be burning lipid fat instead of glycogen, and this will increase your cholesterol levels temporarily. Nothing to worry about, but it frightens doctors. You should also increase fat in your diet to compensate for loss of glucose energy, and this is necessary to prevent your body from scavenging muscle to make glucose for your nerves and brain (gluconeogenesis)