O my invisible but wise women friends, riddle me this!

In this last year of discovering spinning, serious weight training, and now riding on the road, I am also getting sick a lot more often. Instead of an annual headcold as my only malady, I seem to be always getting or getting over some sort of respiratory infection and now sinus infections are getting added to the mix. This is alarming!

It is true that I am now working at a healthcare facility, but I am really careful about handwashing, and I'm getting sick more frequently than my coworkers who have poor diets and no exercise.

Any ideas? I have started to take an enormous multivitamin, echinacea, and oil of oregano. My life IS pretty stressful right now - my husband just finished grad school, debts are high, income low, and I'm working full-time, plus trying to promote my first children's book that came out this spring, and continue to write, and keep our little homestead with goats, chickens, and gardens together. I don't have much leisure/downtime. The bike & the country roads are my refuge.

To the good, I just had to exchange my new 2X Terry shorts for 1X, the hills around here are getting smaller, and so is my tummy.

Thanks for your help!