One thing I've realised after doing stacks of research (I have cPTSD and married to a PTSD sufferer and child suffers from PTSD as well) is that a significant proportion of people who develop PTSD do so because they had some traumatic life threatening event early in life (even going back to birth trauma) which predisposes them to react badly to an event later in life. This is why Person A and Person B are in the same car crash but Person A suffers no long term effects and Person B develops PTSD. This research is fairly new and older Drs may not be aware of it and will say that you can't have PTSD from birth trauma because you have to be able to remember the event. So while I agree with other writers that it's unlikely that a single drug episode could cause PTSD, it could activate an earlier event that was sufficiently traumatic.
I'm sorry you are feeling so awful and know how debilitating this kind of anxiety can be. I was cured of 12 years duration agoraphobia and social phobia in two one hour sessions with a therapy called EFT which is being used in a research program with Vets with PTSD (any war vets with PTSD should google EFT PTSD to participate in their program offering free treatment to veterans with PTSD). It's likely since your event was just a single situation that you could be helped with one or two sessions and it's not expensive. You can find a lot of information about EFT on the web. It's a simple treatment that works by tapping on acupuncture meridians while being guided to think or feel particular things in your body. In simple cases you can do some work yourself but if self work doesn't seem to help, don't dismiss the therapy as it's really most effective in the hands of an expert who can respond to you on a moment by moment basis during a treatment session. It can be done via Skype and several therapists offer a free 15 minute chat before working with you. Don't underestimate it because you never heard of it or because it seems a bit weird. I tried dozens of therapies in the 12 years I had agoraphobia and spent probably tens of thousands $$ before being cured of my anxiety, and it was quick and painless. In my case I nearly died at birth and I believe that's the root of my PTSD.
