breast feeding issues

breast feeding was going amazing at first she latched right away I was over producing milk and pumping after every feed still getting around an oz or two after. then about a week ago she stopped being content started feeding a lot more frequently but throwing a fit at the breast. I took her in for a weighted feed today didn't feed for 3 hours before hand and I only produced an oz. She was crying but unable to latch as breast went soft and stopped producing milk. what could be going on? they gave an electric pump and I'm supposed to bf then pump give her anything I produce and top off with formula 😓