Two weeks ago, my wife gave birth to our 3.7 kg, 55 cm son. His weight dropped to 3.4 kg after the first day, because we did not feed him enough from breastfeeding. Fortunately, he gained back his birth weight on the 5th day with formula and we kept feeding him with the formula. We stopped breastfeeding on the 10th day. Around the 10th day, he weighed about 3.9 kg, and his weight steadily increased to 4.1 kg yesterday, the 14th day.
Things have gone well until yesterday. Our son has been crying way too frequently and sometimes the crying lasts 2-3 hours. In the end, we had to settle him by feeding him, and we are scared that we fed him too much. We usually feed him about 600-700 ml a day. But since he was crying so much and was short on sleep (10-12 hours), we have fed him about 750 ml of formula in the last 24 hours. After the exhausting night with little sleep (I believe the formula we gave was enough), his weight had dropped from 4.1 kg to 3.8 this morning, just slightly above his birth weight.
So now I am really worried about him. Any suggestion to my concern is greatly appreciated!