Even if the blood tests in April came back normal, doesnt mean you are dealing with the same illness. Although you could be dealing with back to back viral illnesses if she goes to daycare and if fever (or fever with a runny nose etc) are present. My 3-year-old went through a stent like that. It will seem like your child just gets over the fever and then maybe well for a week then starts back up..... However, when my 10-year-old son was your daughter age, he ran a fever on and off for several weeks, then kept a fever for 10 days straight. HIs pediatrician kept saying it was viral and just give Tylenol, and FINALLY after 10 days, they did a CBC (white/red blood cell count). His white count was up, meaning he had an infection somewhere. We never saw any other symptoms (respiratory or stomach etc) and the doctor wasnt sure where the infection. Antibiotics got him well. There is nothing wrong with asking your pediatrician to do a simple CBC blood test to check her white/red count for infection, or at least give her an anitibiotic. You know your child best, so trust your instincts. Hope she feels better.
MM
I am adding this to a watch list, as I just asked a simular question.
Good luck!