How To Treat Fever Despite Taking Benadryl And Zyrtec For Hives And Cold?

My daughter has a fever a headache and says her feet hurt when she walks. Says that she feels as if when she walks someone is trying to stop her from putting her feet fully on the floor. She was under the weather last week since Wed and I bought some chewable tylenol. (she is never sick so i had to get advise from the pharmacy) she was seen by a physician saturday as she had developed severe hives friday 4/10. She with a common cold and conjnctivitus also. she has used eye drops randomly as needed and used Benadryl Saturday morning through Monday morning every 4 hours. She took a Zyrtec 4/13/15 at 8:15pm and has had no medicne since. as she is so seldom sick i wanted advice on what this may be