Is it a disease to feel nauseous while breastfeeding?

Patient's question:

09 days
Detailed medical condition and purpose of consultation: Since being one month old, he/she has been vomiting every time while nursing, sometimes not vomiting, sometimes vomiting, and each time vomiting a lot, which is quite alarming.
Current general condition: Sometimes having a bowel movement every two days, sometimes once a day. This time, it has been three days since the last bowel movement.

Doctor's answer:

Hello: To prevent infant spitting up, attention should be paid when feeding:
（1）Do not feed the baby when it is crying.
（2）When feeding with a bottle, the nipple must be fully filled with milk, and the hole should not be too large.
（3）After feeding, hold the baby upright, with its head resting on an adult’s shoulder, and gently pat its back to help expel air from the stomach. Then gently lay the baby on its side. This can reduce spitting up.
（4）Feed the baby at regular intervals and in appropriate quantities. Do not overfeed in one sitting.
（5）The temperature of the milk: around 50℃. Measurement method: Drop a few drops of the prepared milk onto an adult’s hand to ensure the skin can adapt to this temperature without feeling scalded.
Many mothers simply insert the nipple into the baby’s mouth and finish feeding. This method can easily cause the baby to spit up. The correct approach is to first change the diaper, wash the lactating mother’s hands, and gently wipe the nipple with a damp towel. Squeeze out a few drops of milk before feeding, and alternate between breasts to ensure as much milk as possible is consumed. If the baby does not finish the milk, use a breast pump to empty the breasts to prevent mastitis. After feeding, hold the baby upright, with its head resting on the mother’s shoulder, and gently pat its back to expel the air it has inhaled. This will prevent spitting up. Most cases of spitting up in babies are caused by eating too quickly or too much, or changing the diaper or putting the baby to sleep immediately after feeding. After the baby burps, let it lie on its right side. This way, even if it spits up again, the milk will not be inhaled through the nose, preventing pneumonia or even suffocation. However, it is important to prevent milk from flowing into the ear canal, which could cause otitis media. Therefore, observe the baby regularly. If milk is spit up, clean it up promptly. If the baby frequently spits up, it can be