whew, its hard to give advice without feeling like you are going to say something that will get you into trouble LOL
but what i noticed for me that works is increasing my garlic and honey intake which I do even during the summer for allergies, but even more so during the flu season. I bake fish with garlic, i grill vegies with garlic. I drink a lot of herbal tea with honey. I lower my sugar intake because high levels of sugar in your system weakens your immune system. This is why diabetics are proned to infections.
keeping your liver and intestinal tract as clean as possible aids your immune system since a bulk of your immune system is in your intestinal tract. Eating less meats, and increasing your fruit and veggies intake. Also look into pumpkin seed oils because it rids parasites.
and yes lowering stress makes it much worse. I'm a worry wart but recently i found something that helps me a lot because i tend to have an hormonal embalance. I am drinking lots of tea called Women's Liberty tea for hormonal embalance and not only does it relax me but i sleep much better. That is very important to get enough sleep. I also drink teas with Kava Kava, sparingly because Kava Kava can be dangerous if you ingest too much.
also (LOL, i keep saying also), eat organic foods. these foods now days have too many chemicals and growth hormones.
exercising to sweat out the toxins, crying when needed to release toxins as well.
and keep those hands washed and out of your face

. keep disinfectant sprays around you that has specifics for killing viruses as well as bacteria. Whew germs are some nasty little critters, but what makes them worse are people who know they have a virus or infection and come to work coughing and sneezing on everyone else LOL
well i hope that helps, let me know if you have any questions.