8 week old eating enough?

My baby just turned 8 weeks and I don't think she's eating enough...she takes on average 2-3 ounces per feeding. I can count on my hand the number of times she has taken over 4 ounces. She has acid reflux and had projectile vomiting from birth to one and a half months. She has been spitting up and occasionally vomits now. my question is do you think she is eating enough? She eats every 3 hours or so during the day and about every 4 hours at night. I really have to fight with her to get her to finish any bottle. It seems like she has no appetite after she finishes half her bottle! She is peeing plenty of diapers and pooping once a day on average (large). She seems to be gaining weight too. Any help would be appreciated!! Thanks =)