my worst panic attacks had me convinced that I was going to die, literally scared the shit out of me, once I even called my mom to say goodbye because I was that convinced I was going to die, luckily she got me to calm down enough to feel better.
just stopping drugs doesn't mean the panic attacks will stop, I stopped all drugs for awhile and it helped but I still had occasional panic attacks from hell that would come out of nowhere, literally I'd be fine one minute and the next I'd feel like I couldn't breathe, my heart would be racing, I'd feel an intense need to runaway from wherever was...etc. I've never found any specific trigger.
learn as much as you can about panic attacks, if you are hungover or rundown you're more prone to having one but you can have one at any time. my panic attacks led me to benzos which have probably been the worst part of the whole thing because they are very hard to come off of.
the best I've been able to do is recognize that I'm having a panic attack and relax, call a friend if I need to, try and do something else to distract me from that panic feeling. I can do this now because I'm more aware of them and if you can feel one coming on you have a better chance of preventing a full blown panic attack.
for me the panic attacks were debilitating at their worst but I never allowed them to stop me from doing anything, I did have to use meds and in my case I needed the benzos at first I just wish I would have known the consequences of staying on them for more than a few weeks.
hopefully yours won't be that bad, in hindsight I've had the most trouble with them during times when I was overstressed or needed to make changes in my life that I wasn't making. a bad relationship can exacerbate panic disorder like nothing else.
get the help you need, if you end up on a benzo don't use it daily if you can avoid it, try CBT or other things in addition to meds. good luck!