long-term fever with for months, what is wrong with me?

[yrk73]

I have had a long-term fever with very few other symptoms for months, what is wrong with me? I am a healthy 45-year-old female who has had a sleeve gastrectomy for weight loss 5 years ago. I am still considered obese, occasionally have IBS flare up, but other than that; I'm healthy. I have been running a temp of 99-101.5, with malaise, and occasional headache, lower backache (the kind of "ache" you have with a fever). My doctor has done numerous tests that have all came back normal. The only abnormality is I am anemic with an iron level of 9. WBC/RBC count is fine, negative for flu and strep, antibiotics do not rid me of the fever, negative for blood in stools, not a UTI, had a CT head scan for headaches and everything was fine. I am beginning to wonder about something like West Nile or a tick bite. My doctor dismissed my theory.
I'm not sure what type of doctor to see that can help me. Any suggestions on a possible condition or what/where I should go next?