Colic, acid reflux in baby

Ok guys... I have a baby who we have long suspected has horrible acid reflux. He’s 6 w 2 d. He was displaying signs almost since birth. The doctor prescribed him Zantac two days ago. Taking it but no immediate improvement which is OK because I have heard that it can take 5-7 day to see changes. The doctor is pretty sure that it is reflux but told us he could also have colic. My question is... what did you do to help a baby with colic? Did probiotics help? How long did it last? I’m exhausted. Baby only sleeps in hour and a half stretches.