To be honest, I doubt it was laced, there isn't too much you can lace weed with that would be financially beneficial to the dealer, it was probably just a very strong variety.
More likely you suffer from the problems you had at a low level anyhow (depression, anxiety, paranoia) and the strain of weed you smoked simply exaggerated them. Stay away from it in future if it has that effect on you, and definitely don't touch the stronger strains of skunk that are about.