Sick baby help

So Wednesday took my son to the dr. Because he had a wet cough stuffy nose and you could hear the raspiness in his cry and little vocals he makes. I was told it was a cold by the p/a. Took him back yesterday because at times he would gasp like he couldn’t breathe after he coughed and made sure I seen his regular pediatrician. She told me that he had bronchitis and a respiratory infection so now we are in antibiotics. Well today since 8am he has only had a 6oz bottle at 130 and around 4 he projectile vomited everywhere and only one small pee diaper since then too. When I called the answering service the p/a was in call and told me to just mix some Pedialyte with his formula and not to worry unless it’s been 24 he without a pee diaper. Does this sound right To you? He is almost 5 Months old