Flu in 3yr old, and maybe bronchitis help me deal?

My son has been sick since Friday. High temp off and on up to 102. He is coughing so hard he vomits sometimes. I am doing the Tylenol, and Ibuprofen and OTC cold remedies. Also we took him to the dr today and she said his lungs were "gunky" and gave us Zithromax for the lungs. She said he may have the flu too. I am about to lose my mind. He is irritable, whiney, crying off and on. He won't take a nap and needs it. What do you others do to help calm a sick child? Medicaly I am doing all I can. How do you handle all the crying, and irritability? I should know since this is my 3rd boy. My others are 13, and 7, but maybe I just forgot. Maybe just a I understand. I just am at my wits end. He hardly eats, I am forcing liquids and even at that it is minimal just enough for a wet diaper.

I don't have any children, so I can't imagine what it must be like to deal with. What I do know, is that you should stop trying to bring down his fever. 102 isn't that high, especially for a kid. Fevers are a good thing because they help the body to fight the infection. You would be better off just cooling him with lukewarm water to make him more comfortable. Just nothing too cold, or it will make him shiver, which would bring his temperature even higher.
Your son's appearance and behavior are the best indicators of how serious the illness is. Does he look ill? Is he acting much differently? Is he losing developmental milestones? You said he was cranky, but only you really know your son and can determine if you are concerned by this.
As for the zithromax, if he has a bacterial infection, he should start to improve in a few days. If the infection is viral, he will just have to wait it out. His body will most likely be able to clear the infection and he will start feeling better soon anyway. If not, you will just have to take him back to the doctor in case they want to work him up for something more serious.