Cigarette smoke contains MAOI antidepressants in very small doses. Mostly, though, it's habituation. When you started smoking, you probably didn't just smoke a pack a day.
And if you're taking the antidepressants at the recommendation of a GP, find a psychiatrist. General practitioners do not know enough about psychiatry to figure out what's going on. Period.
Ah, yep that explains it then. Smoking was suppressing some extreme environmental stress for me. I will admit that the anxiety got so bad that now I'm on beta blockers. I'm way too young for this lol. Agree with seeing a pdoc. They can not only get to the root of the issue, but sort out medications too.