Spit up or acid reflux?

My little boy has days where he seems to spit up everything I give him. Sometimes it’s A LOT and white/cottage cheese looking and sometimes it’s a little bit and clear. Sometimes it’s even projectile. He doesn’t ever cry or get fussy with it but sometimes he makes a terrible face and occasionally gags. He is 7 weeks old and exclusively breast fed. Usually he spits up a little with every burping session but sometimes he spits up an hour or two after eating. He Weighs 10.8 Ibs. Anyone have any advice. We have an appointment in 2 weeks.