Start taking vitamin C!!! It's water soluble so you'll just pee out any your body doens't use, but I really think it helps. Take a couple of them every few hours. (if you get diarrhea it's too much, but I've never had a problem no matter how much I take, and it often fends off the cold.)
Just dug them out of the med cabinet.....it's probably too late but it can't hurt...