I smoke weed quite often and i have a usual dealer that i get it from but yesterday he couldnt get it to me so he told me his friend would get it to me. I only bought a dime and it was very compacted and stickey. I rolled the whole dime into a joint and smoked it with 2 other friends. I smoked the most. After about 15 min i was feeling baked and very good then all of the sudden i started freaking out! I was so scared and i was screaming. Every thing was in slow motion and i couldnt control my own body or feel pain. I was seeing crazy colours and it sounded like i was under water. All my feeling were amplified. I was seeing monsters in my room and they were yelling in my face. I was crying and didnt know what was happening. It was like i was drifting in and out of reality. My one friend was feeling completely fine (she didnt smoke very much) and my other friend was freaking out too and was puking her guts out.
Sounds like it was a different type of weed to your 'usual' weed. There are many different kinds and all have different reactions to smoking it.