I agree with Grizz here concerning Vitamin D and the blood readings we need so that we are not deficient. D is antiviral but NOT Immunosuppressive, as some would have us believe, but acts as an Immunomodulator/regulator profoundly influencing the healthy expression of our genes (there is a huge distinction).
So how do we receive sufficient Vitamin D in the absence of sunlight (the best source)? supplementation to achieve optimum levels.
CS is excellent as an antipathogen (650ish bacterial and viral varieties).
However, we could have a look at WHY you "caught" your cold in the first place: any viral/bacterial infection (including the common cold) needs a suitable medium within the body in which to take hold and thrive. That medium is provided by something known as toxemia, whether this is sourced endogenously or exogenously. Therefore a body which is free from toxemia, does not allow any viral/bacterial pathogen to gain a foothold, much in the same way that excellent external Hygiene would not allow infections to survive or thrive. How to rid yourself of toxemia? an "elimination diet", or occasional "water-only-fasting", both of which allows the body to "catch-up" with its work of elimination in the nutritional cycle of taking in raw materials and expelling the waste; it is the "retention" of metabolic waste and exogenously sourced toxins that lie at the root cause of many serious and not so serious disease conditions.
Louis Pasteur was quoted as saying "The germ is nothing, the terrain everything".