I just smoked a cigarette

I just smoked a cigarette i know it won’t kill me and I am not a cigarette smoker at all I’ve never even bought a pack ever in all of my 32 years of life this morning with work stress, a coworker had a pack so I asked her for a one it got me feeling lightheaded and less stressed. Has anyone ever smoked a cigarette post donation? I love this community and just wanted to hear some of your opinions on this probably won’t ever do it again.. I am a no alcohol person no thc and vegan now. I always hit my water goals. Now sitting in my office paranoid.