I am 20 years old and in really good physical shape, except i always get sick. My diet is good and I am a nutrition major so i know which vitamins to consume and such. The problem is that i still get sick every time i miss out on some sleep. I don't think this is normal, i had MONO about three years ago, is this because i didn't get rid of it properly? Any suggestions would be great. Also i am in very top notch physical shape, great cardio. the problem is i keep getting colds and throat infections. please help, thanks!