At 40+ i embarked on first attempt to sew from a pattern ! i wear a UK size 16, i got a simplicity pattern in the range 10-20.

I recently lost 3 stone (was a size 22) imagine my horror to find according to Simplicity i am indeed still a size 22 !! (I have a 37" waist) i am very confused that they can be so wildly different. I cannot use my pattern as it only goes up to size 20 it seems !!