My 15 year old has had a fever off and on since Wednesday, various other symptoms at different times: mild sore throat, headache, nausea, lack of appetite. No ear pain. Saw doctor Friday, he prescribed amoxicillin (did not test for strep). She does not seem to be improving, and her fever was up to 104.6 earlier. It always seems to respond to ibuprofen. Any suggestions for what it could be and what else we can do? The high fever concerns me, am planning to call doctor in the morning.