the common cold

I am currently suffering from my second cold this winter. Not impressed. These colds have come after a first time experience with strep throat. I was also not impressed when I had that. All this sickness has made me think, what the heck? What is with my immune system that I am so susceptible to illness. So I looked it up on the internet. What to do to boost your immune system and here was the list.

• Don’t smoke. - CHECK
  
• Eat a diet high in fruits, vegetables, and whole grains, and low in saturated fat. - CHECK
  
• Exercise regularly. - CHECK
  
• Maintain a healthy weight. - CHECK
  
• Control your blood pressure. - MOSTLY CHECK
  
• If you drink alcohol, drink only in moderation. - MOSTLY CHECK
  
• Get adequate sleep. - SOMETIMES CHECK
  
• Take steps to avoid infection, such as washing your hands frequently and cooking meats thoroughly. - CHECK
  
• Get regular medical screening tests for people in your age group and risk category. - CHECK
  

 I do most of these things all the time. My sister has also been quite sick this winter and after speaking with her yesterday she said something that resonated with me. She said I feel like I should start smoking, drinking and being lazy...doing all the right things is not helping. I think I agree with her. Do we try too hard to do all the right things thereby making things worse? Strange logic right? All I know is that I have never been as sick as I have been in the last couple of years and I don't like it. 

Suggestions welcome.