A child being tired like your daughter is IS a reason to give extra cortef (that would be "when the child is just not looking right" reason listed in med literature).   A person being tired can also be a symptom of dehydration (probably mild if no fever or vomiting has occurred).  Which then would wonder if she's getting enough salt if a salt-waster, or if something else could be causing her electrolytes to be off.  Acidic breath, not sure about that, but an infection in the body can cause funny or foul smelling breath (excellent of you to notice that!).  Monthly vomiting, I don't know, but is she getting enough salt & cortef (too low doses of either of those can cause vomiting).  Maybe the meds are getting to her stomach.  If anything, though, being me who has had a CAH child die - I would definitely double her cortef for 24 hours (or longer if need be), and call the doctor, maybe even the ER if outside of doctor hours for an electrolyte panel to see if something is off, also checking her every 1/2 hour & taking her temperature.  There are many flu types going around now, one around here (Missouri) has no vomiting, but a fever comes on suddenly and within a couple hours can be around 103 or higher.  Like I wrote below, there are times the meds may not be being absorbed in their systems and we aren't aware of that - so always be ready to give the injection if the oral meds don't seem to be working.