I’m losing my supply

About a month ago I started supplementing my daughter, 8 months old, with formula. I would pump after she ate and get 4-5 ounces. We had 1 bottle a day. 2 max.

Slowly the amount of breast milk I pump got less and less, I stopped getting engorged and now I get hardly an ounce even after 4-5 hours of overnight.

She has lots of wet diapers when I go a day only breastfeeding, but lately wants to latch more often and gets frustrated easier.

Since she’s almost 9 months now I’m not sure if I should try and get it back up or go almost completely to formula.