being a former smoker, I'm aware of the anxiety one goes through in stressful situations and we all fall back on what is simple and familiar to us. There's nothing simple about vaping until you get very familiar with the equipment. All you need for a smoke is a pack and fire...with vaping, it's a bit more complicated.
Good luck with the stressful situations...but if you're committed, you can make the change...and it'll be for the better! Hang in there!