Breastmilk supply drop at 3 months!?

Betsy

I have had a GREAT supply since day one, sometimes oversupplied. Baby would nurse for 6 minutes on one side and get 3-4 ounces. Suddenly, I’m pumping double / nursing double on both sides to get 3-4 ounces. What is happening?! I’ve not had my period and am 12 weeks pp EBF.