I feel "unreal," "dreamy" when I go to buy cigarettes

Hi!
So I'm a smoker since I was 14. I used to quit, smoke two cigarettes, quit... And when I bought cigarettes, I felt like unreal. I felt like that wasn't happening. It's hard to explain. I felt like I was going to "die", but not in the "real" meaning of it (not a panic attack). I felt more like if a dream was ending.
I have BPD, is this normal?
I'll link my introductory thread here when it's approved for furhter information.
What could I do to avoid this? I usually cut myself when this happens, it seems to relieve it. But when I'm in my way to the tobacco shop, I can't cut or harm myself so...
Cheers!

Note from Lana: Well what happens is that Barbara (the "anti-smoking" woman) tried to prevent Tom to buy cigarettes... Although Tom still thinks he is faking DID