yeast infection

I recently had a kidney stone and went to the hospital. The doctor told me I also had a yeast infection. He sent me home with a prescription but I was never able to fill it. Is there anything else I could use other then the prescription? I put in the prescription Monday would it still be available for pick up this Monday? What happens if it doesnt get treated? How long can you have one? Will it go away on its own? So clueless...