bmi is a load of 💩

So I decided to go onto the NHS website and check my bmi. I'm 9st4lbs. And apparently overweight. I wear UK size 6 clothes (which I think is the equivalent to USA size 4) now I wouldn't say that was overweight.. Yes I have a bit of belly but this is why so many teen girls and boys are developing eating disorders ect!! It makes me so angry... I suffered from an eating disorder and when I was at 6st7lbs I was classed as severely underweight so why, according to bmi, is this a "normal weight" for my height?? PLEASE! IF YOU ARE WORRIED ABOUT YOUR BODY PLEASE DON'T PAY ANY ATTENTION TO THE BMI SCALE!! IT'S A LOAD OF POOP!!