Look into if you have a pregnancy decision health center near you, they have formula to give from donations. Local food bank or WIC, marketplace, ask a family member or close friend or neighbor to help out
Your only Option is formula. Please don’t substitute your 8 mo with regular milk. There’s resources for you to get formula. There’s Facebook groups to help fund you for formula etc. and wic
I know that regular cow milk is not recommended until the age of 1. You can see if anyone in your mom group on Facebook, where you live and see if anyone would donate. You can ask if your local food bank, WIC, local community or pediatrician if they have any.