I agree with Scaredy Cat
I think the initial attack was probably as a result of the anti-smoking medication which I understand are well-known for possible psychological/psychiatric problems.
The power of an initial panic attack is powerful and sufficient to provoke others...especially when alone, in public places, driving etc. The good news is that as this is a relatively new problem, you're in a good place to seek advice and deal with it, nip it in the bud.
For many sufferers the problem has become chronic and entrenched before they start to seek help for the problem.
Panic hits hardest when it first strikes. Recognise your enemy. If you're in a store, don't run. Check your breathing, slow it down, try and focus on something else. If it's bad when you're driving, pull over and do some slow, deep breathing, calm down and carry on. Try not to run away.
Anxiety is very scary but not dangerous. Be determined to take back charge and recognise the symptoms as a fight or flight response.
Good Luck and let us know how it goes