38yo male, 6ft, 182lbs approx, smokes 15 a day, i am a builder have a physical job. usually in good health but every 3 / 4 weeks i come down with a fever, aches & pains, fatigue, allover weakness, inability to consentrate, loss of appotite. but it usually only lasts a day or 2 then back to normal, this has been ongoing for over a year, i would just like to know if i am lacking something like vitamin defficiancy or something as it is starting to annoy me now.