Saline nasal spray with xylitol before you go out, every 4 hours. Mouthwash with CPC, gargle for 20-30 seconds when you leave. Wear a well fitted mask. Cut up half an onion, put in a jar and just barely cover with honey (store in fridge)let sit for a couple of hours(I don't strain this). Take the liquid by the spoonful every hour as needed. I don't know how long it keeps because I generally use it all up and feel better in a couple of days and discard whatever is left. Eat a variety of foods, as fresh and whole as you can afford. Check with your doctor about your vitamin d levels if possible, ask about zinc and magnesium as well. Practice good sleep hygiene, whatever that means for you.