feeding a gassy/colic baby

hi, I like to hear more opinions to feed a gassy baby or what should I not eat to reduce his colic. My LO at 2mths old, bottle-fed expressed milk at 100ml. he has been refusing to drink milk lately and watery poo. Majority of his feeding session we have to burp every mouthful or apply yu Yee oil on his tummy during feeding. Sometimes he get too exhausted and fell asleep during burping and there are times where he drink the whole bottle peacefully.