EBF and trying to pump once a day but nothing comes out

I exclusively breastfeed my 5m old but am thinking about returning to work when she’s 11m old and I want to make sure I have some milk when she goes to daycare. I also want to give her a bottle during the week or if I need to go away.

Prior to last month I had so much letdown milk I collected about 30 bags of milk passively. I had a hormone shift at 4m PP and now i get nearly nothing. I’ve tried pumping (manual hand pump) after the first feed of the day and got maybe a half ounce. I’ve also tried waiting an hour-hour half: nothing. Tonight I tried taking a hot shower and pumping 2 hours after the last feed. Nothing!

Any suggestions? I really want to make sure I have enough milk for my daughter for daycare and if I’d ever like to leave the house!