Talk to Gynecologist on Periods Problem

I had ladt periods on sep 12 till now i did not got my periods i did home pregnancy test it was neagtive than after tht i wnet hosp nd my gynae did blood serum test it was neagtive too And gave duphaston tab fr 5 days /before tht after my 3rdc sec once i had same conditon and dr gave me duphaston nd i got periods aftr 3 or 4 days/now i want to ask is there something to worry or anyone had gone through this same case