Why am i having a discharge?

kso , this is me .. like 5 days before my period , i get a discharge the whole week to warn me i guessfor my period . then after my period, like 9 days l8r i get a discharge for like friggin 10 days ! i went to the doctor to see if it was a yeast infection but the doctor told me im confusing the discharge because with the one for my period .. but its starting to happen WAYY more often ... and it smells REALLY BAD . sorry this is gross .. but do you know whats happening ? what should i do ?