I'm having so much anxiety and it's literally over one cigarette but I want to throw up

I know I'm absolutely ridiculous but I've probably only smoked the equivalent of one pack of cigarettes in my whole life. Last night I had the first cigarette I've had in almost a year and I just feel so much anxiety over it. I don't ever feel the need to smoke more, it was just a social situation where I did it for some reason. How long does it take your lungs to like go back to normal after your last cigarette (if you aren't a normal smoker anyway)? Do you think I still have damage from the packs worth I've smoked in my life?