All perfect praise be to Allah, The Lord of The Worlds; and may His blessings and peace be upon our Prophet Mohammad and upon all his family and companions."Nifaas is the blood that comes out after the uterus becomes empty of the pregnancy"."Nihayat Al-Mohtajj 1/305."
Therefore, the rulings of Nifaas apply to a woman once her uterus is empty due to the delivery of an actual pregnancy, which is usually detected by the ultrasound test.
Thus, a woman is considered in a state of Nifaas after she delivers her embryo, regardless of its age. If she delivers an actual pregnancy, the rulings of Nifaas apply to her; therefore, the blood coming out after your(Asker) miscarriage is Nifaas and its rulings apply to you. And Allah knows best.