I just thought I would reply about making a useable scale, seeing as a few people have mentioned that this is not an intuitive process for them.
Any scale needs to be defined before it can be used, and defining it can be part of the process to helping to manage whatever it is measuring.
As has been mentioned, when we are in the thick of something it is all too easy to just know that we feel 'Bad'.... by introducing criteria by which we can assess and grade how 'bad' we feel we start to introduce nuances that may have previously been overlooked. A whole week might have been 'Bad', but with nuances in place we may be able to identify some ups and downs, over time we can notice trends and patterns.
Starting a 1-10 scale might be a bit daunting, so to make it easier I like to break it into several steps.
First define 3 levels, Zero, Maximum and Middle.
Depending on the scale and on your experience these are going to vary, but something like:
Zero= "Everything is fantastic, I wish life were like this everyday, I feel great and have no signs of symptom X"
Maximum= "Totally unable to function, unable to perform basic self care/fear of immiment death/Physically unable to breathe/move even to protect self."
Whatever is in the maximum section - make it REALLY maximum. This is not a state that you could sustain for an entire day, let alone years. This is a state where calling 000 would be involved.
Middle= What is the logical midpoint between these two extremes? Something like "Experincing symptoms but able to peform necessary functions and can still enjoy some aspects of life. It would be hard to go on like this but I could manage it."
Now you are going to define to two midway points between Zero and Middle (I'll call this Midlow), and middle and maximum (MidHigh😞
What is halfway between Zero and that middle point? MidLow
Maybe something like "Some symptoms, but able to perform most functions that I want to with some effort. Able to enjoy plenty of aspects of my life. Not feeling too limited. Could carry on like this indefinitely"
What is halfway between the middle point and that maximum? MidHigh
Maybe somethign like: "Able to perform necessary functions with considerable effort and distress. Difficult to find aspects of life that can be enjoyed. Would be very difficult to go one like this for en extended period of time."
And then lastly you find the remaining midway points between Zero and Midlow, Midlow and Middle, Middle and midHigh, Mid High and maximum in the same way (what is the halfway point between each pair).
Get it all written out into a list and number each bit 1-10. Hey presto, you now have a scale tailor made for YOUR experience.
And because it is just for you and your experience you can tweak or adjust this as you go along if you come up with any better defining attributes along the way.
I personally tend to think of it as TWO scales which work simultaneously but in opposite directions - Ability to Enjoy Your Life, and Distressing Symptoms, but you might have a different way of thinking of it.