Smoking?? Has anyone else felt this way!??

Now we all know smoking cigarettes is bad for the baby yes I know this, I used to smoke a pack a day, and when I found out I was pregnant I cut back a lot, I'm now down to 1-2 cigarettes a day. Which I think I've done a good job at cutting back as much as possible. I am starting my second trimester tomorrow and I promised myself and my baby I will quit for good. I smoked 1 today and I feel horrible but I think starting tomorrow none and I will be good! They have been making me not feel good too!!! 
Is there anyone else who experienced this???