My son (almost 4 yr old) had similar symptoms. Last week, he had a mild ear infection ... got antibiotics for it last Friday and everything got better that weekend. But by this past Tues night, he fever came back, coughing fits with vomitting, some diarrhea...mostly vomitting mucous/phelgm. And yes, it happened a lot. I changed bed sheets usually 2 times at night. His fever stayed with him (but controlled with motrin and tylenol) for 2 days straight so that's when I took him into see the Dr. (they said if a fever persists after 2 days straight to bring him in). She said he probably has a throat virus ...that's why it's not improving even though he's already on antibiotics. With a virus, you have to just wait it out and treat symptoms (cough meds). She took chest xrays to make sure he didn't have fluid in his lungs...and they came back normal.
Dr. said this throat virus is very common right now...going around to many kids (i've heard about through other moms too)....similar symptoms, vomitting, diarrhea, coughing fits, fever.
To combat dehydration, I had my son carry his sippy cup (largest one I can find) full of ice water. And every time he coughed, I instructed him to take a sip of water....that helps calm him down, calm down the coughing fit..and keeps him hydrated. he slept with this cup and would take sips throughout the night and during his coughing fits. I stashed water cups everywhere throughout the house so they were within reach for him whenever a coughing fit happened.
And just give water only....sugary juices can dehydrate. Dr. said that as long as he's sick he may not eat well at all...and that's ok for the meantime...she's just concerned with keeping liquids in him...popsicles, water, soups, etc.
Well, he continued his fever yesterday -- got as high as 103.9! But once i would give meds, and if i gave them every 4 hrs...and stayed on top of it...his temp would be in control. But today, Sunday, he's much better. No fever since early last night. Coughing is infrequent. No vomitting last night. He slept all the way through the night. So he's on the road to recovery.
Call your Dr. again to explain your concerns. It doesn't hurt to call. If anything, whenever I call, I at least feel reassured after I've received an opinion from a medical professional.
My Dr. told me that if his fever spiked to 104 or 105 to call them immediately or if the fever never responded to tylenol/motrin to call them immediately, too.
But just wanted to share that my son had been vomitting every day since Tues night, too. Stopped yesterday, during the day. And the vomitting was mostly mucous...not necessarily food/liquids...and not constant. mostly just at night when he went to bed. His diarrhea didn't last that long...maybe just 2 days. And my son would shake/got chills when his fever was too high...and he wanted to be wrapped up with a blanket...but once the tylenol/motrin took effect everything would be fine.
If your son's fever is not being controlled with tylenol/motrin, I would definitely call the Dr.
Give us an update, when you can, on how he's doing. I'm praying he heals quickly!