Is this also a sign of an eating disorder?

If you know that the symptoms are bad (eating too little, constantly weighing yourself, exercising until you collapse, feeling dizzy) but you think that everyone who says you look normal and not fat is lying or you think you should know better because you can hide a lot with clothes, you think that all the calorie requirement calculators on the internet are wrong and that you have a much lower one.

When you think every day that today was way too much and you have gained weight but nothing has changed on the scales or in the mirror and you then think that the scales measured wrong or that you don't notice two centimeters more in your stomach circumference.

But when you go from 53 kg to 48.7 kg and you don't see anything at all in the mirror.

Is this also a sign of an eating disorder?