I had exactly the same experience like you when he was between 1-1.5 months old, he seemed very uncomfortable, I asked the nurse before, they checked him and said he is ok not sick and it's normal, now he is 2.5 months old, I only breastfeed him once a day, he has poo once a day only but the "gu lu gu lu" noises has gone. If you worry, better consult with your paediatrician