8 month old on a bottle strike?

I don't know what to do. She isn't drinking nearly as much as she used to. She used to drink just under 10 oz a bottle and now she drinks only 4, if I'm lucky. Sometimes only 1.5. She had 19.5 oz total today. I ordered a faster flow nipple for in case it's that. I read it may be sore gums from teething so tried giving her her baby gum stuff to help with the pain first but she still won't take it. I always offer bottle before food but a lot of times lately she will throw herself back and fight her bottle, but will instantly take real food. Her poops are still soft so I don't think she's dehydrated, but I honestly have no clue how she isn't because I feel she isn't getting enough formula. Any tips to help? Or advice in general? She's been so extremely difficult in general lately. It's killing us