So confused

I'm on cd 39 with nothing but bfn. I've been taking progesterone to help lengthen my cycles and help support implementation. I called the dr today and she said that I'm not pregnant and she would give me something to start my period. I picked up the prescription today and it's the same thing I've been using but oral vs vaginal??? It seems to me they are giving me the same medicine to do 2 different thing, do you think the pharmacy made a mistake? Anyone have  any insight? Does the oral vs vaginal make a difference? Thanks in advance and good luck to everyone!