I physically couldn't stomach a cigarette when I was pregnant, it made me retch. The smell on other people would make me physically gag too.
Having one is just not worth it, it'll likely either make you want another and then another, or make you throw up.
How far along are you?
And I personally consider the "the stress of stopping smoking outweighs the risk to your baby" to be a load of bollocks, a line rolled out by so called professionals to placate you about smoking in pregnancy.
Your baby isn't craving a cigarette, you are. Your responsibility right now is growing a baby, not pumping your placenta full of nicotine and reducing its ability to function correctly.
A 'friend' of mine smoked throughout her pregnancy and then in the house. To the point where the birth announcement photo shows an ashtray on the sofa end in the background.
She now regularly posts on SM things like 'DD coughed so much last night, she was sick in her bed, I feel so bad for her, I can't do anything to help'. 
It's hard, yes. But worth it. Nothing that is worth it is easy.