My 5mth old boy could actually drink 150ml of milk every 3hrs. But starting from last week, he only drinks 30-50ml. Now he is sneezing and hving cough, he is still drinking 30-50ml every 3hrs. I have changed the teats already.Is tiz part of teething?

He may be feeling uncomfortable due to the illness that's why he is feeding less. Just make sure he is peeing well. Won't rule out teething coz some kids teeth pretty early. There's also milk strikes. My girl had her first milk strike at 3 months old. It lasted for about 4 days.