Your post is confusing, I can't understand what you're talking about. Rewrite it in a more understandable format and I might be able to help. So you get sick when you're tired? Sounds like you need more sleep.
Yes it's normal, using so much energy via stress or exercise or just typical physical activites can suppress your immune system and make you more suseptible to infection/colds/etc. Best thing to do is get enough sleep, eat when you should, stay hydrated, VITAMIN C.