Low wbc and high monocytes...15yr old daughter

[R.status]

My daughter who is 15 started coughing 3 days ago and spiked a high fever of 102 yesterday. CBC showed White cell to be 2.5....her normal for the last year or so has been 4.9-5-9. The monocytes were high...i believe it was 18. They tested her for mono and it was negative. I've been concerned about her white cell count for the last year because it was on the low end of normal. Her doctor said that for some people it's just normal to be that way. She has been taking Nasonex for the last year and I asked if that could be lowering it. He said no. I looked it up and it says that it can lower white cells?? Could this be a virus. I asked him point blank if this is something to be worried about. He said no. I asked him if it could be Cancer. He said no. She is coughing horribly and sneezing and blowing. Should she be on an antibiotic, or will that lower it even more? He wants me to bring her in the office for a recheck in a week or so. I think I should take her sooner? Why would her monocytes be high with a low white cell? This has me very scared. The first thing you see when you research it on the internet is Leukemia.