Breastmilk drying up on period???

Hi, my baby is 5 months old and has been exclusively fed breastmilk up until last week. I am on the depo shot so I haven’t had a period in about four months. But this week, I got a couple days of spotting so I’m assuming it’s a period. My milk had all but vanished and I had to supplement two bottles of formula per day. She is also sleeping through the night, and I pump when she’s asleep. Try to nurse every 2-3 hours during the day. Got my lactation cookies that I had run out of and stopped taking reglan due to bad thoughts. All of this happened at the same time. My supply is somewhat coming back up, only had to use one bottle of formula yesterday. My question is, will my supply come back if I keep pumping a lot and trying to nurse? She gets impatient and won’t stay latched if no milk. How long will it take? I’m so sad and thinking our breastfeeding is about to end.