4 month old feeding

Emily

My 4 almost 5 month old refuses to eat more then 2 oz every 2-3 hours now and I’m not sure why 😩 she used to be eating 4 every two hours and just out of the blue won’t take more then 2 and I have no clue why or what to do. I told myself I would stress until Thursday night but I’m stressing after only a day and a half. Any suggestions as to why or how to get her to eat more??