3month old never full

My nearly (just a few days short of) 3 month old seems to never be full. We talk to her pediatrician in a few days but any suggestion on what might be a solution. She refuses a pacifier and literally can up to 8 ounces but most of the time it's 4-5 ounces every 1.5-2 hours through the day then she sleeps all night and wakes up in the early morning to start it all over again.