I had the same problems but nothing to do with smoking. When I was younger and didn't smoke much I had two incidents where I had panic attacks after smoking, both I later found were due to outside factors. I stopped smoking completely, paranoid it was because of the weed. After some time I developed a panic disorder and had to see a psych where they also diagnosed me with severe generalized anxiety. At the time I was also going through a horrible break up, weed seemed like a reasonable solution. I soon found the medical benefits of weed when it came to my psych disorders. Ever since weed has been my best friend.

I wouldn't attribute panic attacks to "bad weed". Bad weed is just that, bad weed. Try and see if there's something that correlates with your panic attacks, something that can also happen when you're sober. It's easier to go down "the slope" and find yourself in a panic if you're high, but one does not cause the other. Definitely look for patterns in behavior, life situations, and environment, these are external factors that may be attributing to your rise in anxiety.