You are expecting a miracle over night. It takes a little longer for the med to suppress the yeast and then for you tissues to heal from the inflammation.
As an aside, stay away from the 1 day treatments. You are much better off going for the 7day. 1 - it will help prevent and allergic reaction to the med. The dose in the 1 day is pretty strong. 2- it takes more than one day to deal with the infection.
Also, it just may take more than one treatment anyway. If you are in the habit of using the 1 day treatments, you could set yourself up for resistant infections. If you have had more thant 3 or 4 yeast infections in a year, you might want to think about what might be causing them.
It could be a bacterial problem. I would see the doctor again and have him run a culture.