How long does it take to stop feeling stressed when you quit smoking?

I quit smoking 4 days ago…i started to exercise and will continue to everyday…it helps alot when you want to quit smoking…the thing is that i feel very stressed and sensitive with everything…i get really nervous and shout at nothing…i did smoke one cigarrette today and half yesterday…but before i was smoking one pack of cigs a day….so i feel much better and i’m starting to feel discusted by cigs…the one i smoked today made me feel dizzy, smelling aweful….i’ve been smoking for 7 years though…i’m i doing it the correct way? When will i stop feeling nervous and stressed? Does it matter that i smoke 1 cig when i feel really anxious?