I've had so many freakouts on pot.
One time, I was at a house listening to my friend jam with his band. There were a lot of people around that I didn't know. I was smoking this frosty silver-green bud, but the effects took a while to come on, so I just kept smoking.
Suddenly, I got the impression that everybody at the house was sleepwalking. Like I was the only one truly awake or something. Even as I looked around me, I noticed people were making an effort to shield their eyes, like they were refusing to see reality as it was. I became convinced that a portal to another dimension was opening up in the ceiling.
Immediately I went outside to get away from it all. I stood outside in the dark, and the moonlight was passing through me like I was a clear crystal of gypsum. I became convinced that some of the people at the get-together were plotting to kill me. I went to tell my other friend that I was leaving. He has some emotional problems, so I knew he would understand. After leaving, I felt better instantly.
Other times, when smoking during a movie at night, I have gotten the impression that my actions were being recorded by some spy outside. It's not like I could be jailed for smoking pot or having under an ounce of weed, but a part of my mind sees all the possibilities, including the improbable ones.
Mostly my freakouts happen because of the high amount of energy pot produces in my body. If I'm not doing anything to work out that energy, it becomes a negative force.
Pot can be a tool for personal growth, a way to work out your fears by imposing them upon you. When used too often, if you fail the test too many times, it can put you into a state of non-growth.