Why does smoking weed not feel the same anymore?

I used to smoke everyday usually a few times a day and it was great. I tried K2/Spice stuff a little and learned that I didn't like it so idk if that might have something to do with this but i almost feel like it does. One night i smoked some bud with my friends and we went and watch Saw 3D. Only a few minutes into it i started getting very disoriented and felt sick. I took my glasses off then suddenly everything went black and the next thing i knew my friend was shaking me asking if i was okay and i woke up. he said my muscles were clinched up very tight and my eyes were open but i wasn't responding. we left and i threw up a few minutes later. I smoked a few times after that but then i quit for wrestling season. a few months later Ive tried starting back and it just hasn't been the same a mostly not enjoyable. Sometimes it seems okay but other times its bad. my heart beats fast and i seem to get real paranoid and think too much. I've been trying to figure out if this is just a mental thing i need to get out of my head or if i just can't smoke anymore. Has anyone else had anything similar to this happen???