I have allergies all yr long. does that mean my immune system is extra vigilant to all invaders or does it mean that i am more likely to get sick?

Not all invaders: Your body is indeed hypervigilant but not to all invaders, only to those you are sensitized to. Allergies develop because your body recognizes specific things as foreign and over-reacts to them. If your allergy symptoms involve irritated and swollen nasal tissue, open skin lesions, things like these can make you more prone to infections.