What's considered yoyo dieting? My weight ranges 3-4 kilos depending on metabolism or anxiety. Is that a normal fluctuation?

Normal. Yoyo dieting implies that someone diets and loses significant amounts of weight (greater than 20 lbs) and then regains that weight, and usually more, after stopping the diet. The fluctuation of up to 3-4 kilos ( 7-10 lbs) can be normal in a reproductive aged female with normal and predictable cycles. These changes can be a result of stressors, hormones , etc and are not worrisome.