@Gelati: i have no idea if it is from the formula or the BM or both?! Mom is suggesting me to stop BF him for 2 days and see if there is any improvement. I don't feel like giving up on this one but i might have to if it still show no improvement. Well, it has been a week!!! I am not so keen to change formula because i have no idea what to change it to. NAN comfort supposes to be gentle on the tummy!
Be careful with BF if you might have low supply issue. In early days, bub could seem satisfy with my BM at first and then he went on a crazy starvation mode few hours later. Or he just wakes up in less than 1hr demanding for another feed rather than his usual 2hr feed. That's restless. Now, regardless of how many BM i feed him, i always prepare a 90ml bottle. If he finishes that as well, i put him back on my breast.