Hello,
I have gone through your query and understand your concern.
First check her temperture. If it is more than 99 F, then she is having fever.
Usually child do not complain of fever.
In turn,they may express as
body pain and fatigue and also looks sick.
If the fever is high, give her some NSAIDs like
Paracetamol, or
Ibuprofen.
You have not mentioned why you have given Guaifenacin.
Guaifenesin is an expectorant that helps thin and loosen mucus in the lungs, making it easier to cough up the mucus.
I suspect she may have upper or lower respiratory infection.
It is usual to have fatigue and
body ache in respiratory infection.
Show her to your treating doctor and get treated early.
He may add antibiotics to her current medications to treat infections.
Do not wait for any emergency problems and take her to ER.
Hope this helps.
Please write back for further queries.
Wishing you good health.