From a long time every month during my periods... the first or second day(almost first only) I use to have severe pain in my lower abdorman (and back also) and this pain will be 3-4 or more hours till I dispose a blood clot (not too much just like one finger length ).. after that my periods will come nrml... and after the end of my periods within one week I use to have something white(colourless) like blood in periods for 1-2 days... is everything normal in my periods...