A virus can last a looooong time. Think about times you've been sick....it's been longer than a few days hasn't it?
I would just rest rest rest as much as you can. Start giving her some probiotics with maybe pedialyte (unless you are still nursing, then just nurse nurse nurse) and you can go to a health food store and get some echinacea or Kick it Immune for kids and just dose her up to build her immune (these herbs are safe for her age).
There is a product called Temp Assure that will help her control her temp....I would hesitate to keep her on acetaminophen or motrin long term....a low grade fever is good to cook out the bad stuff (yes, I know they make them feel bad). Maybe just give the hard stuff to her when the temp peaks in the afternoon/evening?
Put some eucalyptus oil in a humidifier at night to help her coughing...
Are you taking a good rectal temp which is the most accurate?
My 31 month old is going on 3 days of a nasty tummy virus and it's the longest he's been sick. You need to ask yourself...what is a doctor or ER going to honestly do?
Dehydration? Yes, go. Fever OVER 102.5 that you CANNOT control or bring down under that? I would go. Lungs don't seem clear? Go. If she is tugging at her ears leading you to think she has an infection...okay. Do you get my drift?
Other than that, you can care for them at home. If you have a doctor that is hesitant to put her on antibiotics, I would listen to him. If her lungs and ears were clear 2 days ago and she hasn't gotten worse, just stayed the same or had glimpses of getting better, just ride it out.
The hard part with these guys is they feel better, they go play and then they feel worse. Think about when you have been sick and you over do it and then are feeling rotten again.
Good luck mama, these are never easy times with a sick kiddo!
A reminder: Ibuprofen is great for a fever, but needs to be taken with food because it can hurt her stomach....so, if she is throwing up at all and has a fever that is low enough not to worry (I wouldn't stress about 102), then I would recommend acetaminophen)...or try the Temp Assure. And follow the dosing on ALL bottles! They all have limits....don't just dose every four hours. Remember, a higher temp means the body is NATURALLY fighting what's going on...let it as much as you can. If it gets too high or they are too miserable, then bring it down. But don't don't don't over-medicate for a low grade temp!