I think there are two possibilities for this reaction to pot...it was either laced with something or you are just one of those people who get ultra paranoid on pot.
My first real experience w/ pot was pretty funny, but not at the time. My boyfriend, Nick, had blown some smoke from his mouth to mine but I never felt anything from it. Then about a month later we went to some of his friends house, people I was just meeing for the first time. I took 5 hits of some chronic stuff. I sat on the couch and was tripping out. Going in and out of waves of really being there. After a while I knew I wasn't right so Nick told me to get up and get some water. But when I stood up the headrush really sent me.
Being that this was the first real drug experience I had after coming out of the Borg, I thoroughly thought I was dying. I began yelling at Nick to take me to the hospital because I was overdosing on pot. Nick chuckled because no one ever OD's on pot. He walked me around the block so the fresh air could clear my head.
I was crying hysterically and so embarrassed to have done this in front of his friends I demanded he take me home. I cryed the whole way home and vowed to never do pot again.
Of course, then I got home and had the most amazing sex of my entire life. And it all made sense. We laugh now that it was both the worst and best night of my life...all due to the same thing.
Pot has never had that affect on me since. In the early stages I felt the waves more but never much anymore. I do know many people who simply cannot do pot. They stay highly paranoid everytime they smoke it. I guess it depends on your makeup.
I personally am scared of hullucinating drugs. I've talked to freinds about acid and find it wierd that they think it's great to sit in front of a mirror and see yourself as 100 years old or with some gross stuff coming out of your head. I just don't think I could handle it. I do very occasionally drop E, did it this weekend home alone with Nick. It was super mild, to me anyway, Nick's a lightweight. It definitely not something I would do much. It had been 1 1/2 years since I had done some good E. But the 4 hours of intimacy w/ Nick was so well worth it.
But it is not to some people. Again, some people either have a different reaction than most or simply do not like the feeling.