Period or Breakthrough bleeding on minipill

Cris • Hi I’m new :] I’m 19

I’ve been on norethindrone 0.35 mg (POP) for almost 2 months now, and I’ve been getting medium heavy bleeding, not enough to fill a pad. This is so scary. Is this a period or breakthrough bleeding? It has lasted for 3 days. I’m apparently not due for my period for another two weeks. It seems like the blood is progressively getting heavier over time. Plz help, I’m so scared rn. I’ve been told it’s just side effects