What Causes Yellowish Foul Smelling Vaginal Discharge?

Hi, Ive had a discharge for a while now and when I went to the doctor and got swabbed she said it was a yeast infection. I took the oral pill and put the cream on as much as i could but it did not go away. I have stopped but for the past few days its been really heavy. It is cloudy and white with a small yellow tint but I do not know how to get rid of it. There is an odor but not very strong, what could it be? I also smoke a lot of marijuana, does that have any effect to it?