My son is 2.5 months old. He has been breastfeeding (only left side, does not feed from the right) and drinking formula milk. Since last 5 days he has been spitting the formula milk out every single time. He only drinks formula milk during the night when he is sleepy and that too in lesser quantity as compared to earlier. His intake has reduced. My wife isn't producing enough milk. Hence we are concerned that my son is under-fed and always fussy. Kindly guide.