Have had a fever of unknown cause the past few days peaking at 102.5. saw doctor- negative for covid, negative for mono, negative for strep, chest x x-ray normal, but cbc showed a wbc of 2.4. is that concerning?

You don't mention what your symptoms are or what the differential component of the white blood cell count is(%of polys, lymphocytes),. Viral infections,which is what you probably have, can temporarily suppress the bone marrow's production of white blood cells. I expect your wbc will return to normal when you recover from this present presumably viral infection. Your MD will follow-up appropriately