take PROBIOTICS!! If you have enough of the good 'germs' around you won't succumb to the bad ones.
Also, it's imperrative that you have really good microflora for your baby when it's born...the bacteria s/he picks up coming down the birth canal is hers/his first defense against any illness. The next is breast milk.
There is tons of medical research on this and it is just barely becoming mainstream.
Especially Nerdymom, if you have a stomach bug go to the health food store and get live culture kefir or kombucha or high quality (no sugar) yogurt or real fermented sourkraut and drink/eat as much as you can. If you don't like any of that fermented food, buy supplements that contain: acidophilus, L. bacillus, and L ruteri...at minimum (I think the best one is Biokult) and take really high doses of the supplements to help populate your gut and fight the bad guys!
Here are 3 short abstract/articles showing benefit of probiotic use in medical world.
There is a lot of hypothetical discussion in the medical community that the hygeine hypothesis (keeping everything clean to stay healthy) is what is causing many infections and diseases...because we are TOO clean, we don't have the good bugs to fight off the bad ones.
Kids growing up on farms have less allergies/asthma/illness than those in suburbia...which kids are in a cleaner environment?! Same with households that own pets as opposed to those that don't.
I am passionate about this good flora thing for infant health as I am about breastfeeding for infant health, because they go hand in hand for the baby's immune function. oh...and just one bottle of any formula changes the infant's gut flora (which is very special and protective) to an adult gut flora (not protective) from then on. (scroll down to 'Acquisition of gut flora in human infants' in this wikipedia article: http://en.wikipedia.org/wiki/Gut_flora )
Let me know if you would like links to support that, there are plenty...it's fascinating!
(oh yes, and to fight colds and such, Zinc, Mg, Vit c in high doses can only help your immune system fight it - the baby needs those nutrients so depletes you of them)
Hope you feel better soon
(I and my family just got over cough/colds, too)