Cbc performed-everything normal except low wbc. blood smear- normal. told to come bck in 2mths & redraw. should i be worried? wht could cause this?

Probably normal: If you are not at risk for hiv, then you may represent the low end of the bell curve that makes up the "normal" range for wbc. Some people have immune function issues with chronically low counts, others just "rest at low idle" and still ramp up when fighting an infection. See what follow up test shows.

How low?: As previously mentioned, your low white blood cell count could be the very low range of normal (it depends on how low your wbcs were). Another common cause of a transient low WBC is an infection. If you had a virus within the last two weeks or so, it can suppress your wbcs. This will get better on its own. Why did you get CBC in 1st place (symptoms)? Rechecking in 2 months is good idea.