What Causes Delayed Period After Having Folic Acid And Duphaston?

hello doctor, i am 24 years old women and trying for baby since last 3 months. my doc gave me folic acid and duphastone which i took from 18th may to 23rd may according my doctor. my period date is 9th may. today is 30th may means i missed my period date.i also feeling pain/cramping in my lower stomach since last week to till now.is it my delay period or m i pregnant? how many days take to get period after stopping duphaston. plz reply soon.thnx