Weight is the force we apply to the ground, why then do I care about it? OK so when you have extra fat you press on the ground more than you would if it just vanished so it can be helpful to monitor changes in fat levels.
But weight is an indirect measurement of fat, even clever scales don't really measure it, you need CT or MRI or total immersion in water or something. Lots of other things effect it, in particular hydration levels and the contents of bowels and bladder. So you exercise and burn extra fat but you also build muscle, that adds weight! Should you feel bad? NO because muscle burns energy and that will mean more fat burnt. But it is frustrating as you are measuring your progress via weight change and you always feel unsure about the measurement. So you can do a few things to help like measure yourself, photograph yourself (even just your face) and also just consider how you feel. That way you are not a slave to the force you excerpt on the earth's surface.
Another thing I have found helpful is simply just to say "my weight is below X kg or lbs, a few weeks ago that would have been impossible no matter how little I drank and how much I went to the toilet or indeed worked out." our weight fluctuates so much it can make you feel like he ultimate dieter one week and a failure the next but this mind set lets you see the important drift.