I don't know if it brought it on or just kicked it up, but right before I was fully diagnosed, I ate a marijuana treat. I got a BAD panic attack and thought I was going to die. After, I noticed my anxiety got worst. I use to smoke a lot of weed when I was a teenager, 16 - 19, and I'm beginning to think that it can be linked, but I'm no expert, so.
I agree with what LindaRK said:"Instead of trying to figure out where it came from, best to address how to learn to manage it".
Best of luck.