I have 2, 2mm sized stones 5 cm away from my bladder. Two nights ago I had horrendous pain, frequency and vomiting, which lasted for about 7 hours. My question is, could the stone(s) have passed without me seeing them, even though I am checking for them after each visit to the loo! Also, I know they are painful when passing through the ureter, is it possible that I wouldn't feel them when they leave the urethra?