How to prevent caching an illness when you've already been exposed?

I've actually been eating nothing but veggies, lean meats and drinking orange juice and water for the past few weeks. However, within that time my husband got so sick I had to take care of him. I was beyond exposed to whatever he had, he was running a fever of 103 for days, complaining he was so cold, and half the time I was holding him and sleeping with him making sure he stayed as warm as possible. I was getting coughed and sneezed on left and right :(! He went to the doctor and they said he had pharyngitis, strep, etc... I don't feel any symptoms but I'm afraid if I do it will hit me like a brick. I'm now drinking loads of OJ, eating only high quality foods, and stopped smoking. I don't know what else I can do for my immune system, any tips??