if im not mistaken, the hormone pills are just to make sure you are on track for the pregnancy.

Progesterone helps thicken the lining of the uterus to prepare for a fertilized egg.
So if not enough progesterone, can have miscarriage.

Ur period also irregular (means hormone irregular) hence ur doc give you progesterone just to be on the safe side.

Until next checkup with ur doc, he will advice you if need to continue or not.