Don't worry it happens there is nothing wrong with your milk
I passed by this and I didn't give my baby formula only breastmilk, it's a phase where a newborn demands to be fed every 20 mnts or so for me it lasted 2 days, studies say that it's a phase of them growing so don't worry just offer breastmilk than rest while they nap than yr breasts will be full in no time
Good luck sweetie