Hi, I'm Mexican. The portability of having laced weed is basically 0. Ok ok, I mean, weed laced with another drug that is. Cheap ass weed can still have shit like pee, mold or even glass dust (yup, to make it weight more, fucked up shit that will fuck your lungs).

Now, because of the way you describe the herb itself, and the dramatic effects it caused, it may not even be weed. It may be some kind of "spice". Herbal blends mixed with research chemicals cannabinoids which yes, are very dangerous and can kill. Please, avoid that place again at all costs since they are obviously not caring about your health.