There are many ways to measure yourself. You can measure yourself in feet, inches, meters, centimeters, pounds, kilograms, stones, degrees Fahrenheit, Celsius, years, months, IQ, EQ, dollars, cents, Euros, shillings, grades, degrees, personality, friends, happiness, suffering, and so on and so on. All these ways of measuring yourself represent ideas about yourself. Each form of measurement though, is as imaginary as your self.
They are all real ideas, just like the idea of your self is real. Measurements break things down and provide new perspectives on how to look at things. A tree is the height of a tree regardless of meters and inches. We can take the tree and cut it up into 2x4s and we have all kinds of measurements, but no more tree. A year of our lives has so many days and nights and events. Those events go on regardless of how we divide the time.
The idea of a separate self is just another idea of measurement. Instead of one entire universe, there is a universe made up of so many parts and we count ourselves as one of those parts, separate from the whole. For some reason, that basic measurement, making two out of one adds to our experience of suffering. It’s unfathomable.